Cheap deal recommendation for this week.  https://www.aliexpress.com/item/33012900540.html 

LIke most chinese products, sizing runs rather small. You probably need an XL and if more than 33" they will all be too small.

More tips on AliExpress:

 With most sizing from China you have to read the chart, convert from Centimeters to Inches, and when they have listed the width, double it for the waist. It helps if you have your waist and hip size measurements, in CM, and weight in KG, taped to your monitor.

For example the shiny G-string, which I linked to previously   https://www.aliexpress.com/item/33044626941.html
Waist size for XL is listed as 38. But they are measuring just the width when laid flat. So 2x38 = 76 which is only 30 inches.
A good example of why anyone who is not super skinny often needs to order the XL or XXL by default.
These will stretch a bit, so someone up to 32" waist can fit in the XL.
But being of shiny fabric it WILL lose its luster, even when carefully hand washed and air dried. 

However at that price, if it lasts a season or two it is still a good deal.

Other vendors, like for this thong, list by height and weight.  https://www.aliexpress.com/item/33059394023.html
This is a thong with more front coverage, but as you can see by the pictures a rather light weight fabric. 
They size by height and weight table, although I have found the XL in this to be about a 32 to 33. 
Lighter fabrics like this tend to have more stretch, but if too large have a tendency to gape.
As with all very light weight fabrics it is generally a good idea to get the dark colors, especially if you are going to get them wet.

A thong with a flat cut as with the last one is more likely to gape or fit incorrectly than one with a center seem and a bit of a front pocket. 
A thong with a center seem like this https://www.aliexpress.com/item/33037194282.html 

or a defined pocket like this one :https://www.aliexpress.com/item/32997304539.html 
is more likely to fit correctly up front. 

As is this one: https://www.aliexpress.com/item/33057404164.html 

Both of the above are rather thin, so you may want a dark color or at least a dark color for the front panel. 

Sizing from China can be strange and confusing.  Here are some suspender thongs, https://www.aliexpress.com/item/32800488012.html
They have sizing, but I can't figure out what would be the significant difference between a Medium and a XXL would be, because the front and back are not attached, and the straps are free floating. 

Other vendors, selling TM or UM thongs, you are going to need the largest size available. For example these micro shorts https://www.aliexpress.com/item/32675885256.html
An XXL is about a 29 to 31 waist size. 
I recommend avoiding any TM or UM style thong with a flat cut front, (one that has no center seem or pocket). 

Sometimes you just have to guess, and if the suit is not quite right order a second one a size larger or smaller. Now you have one to donate to the SunSplash wall of thongs that don't fit !!

As I said before, AliExpress is a bit like ebay, in that they have listings from many vendors. You can find the exact same product listed by a number of people, but for different prices and shipping costs. AliEpress only allows you to sort by price, not 'price and shipping' like Ebay.  

To figure out which vendor to buy from it helps to compare the identical thong from different vendors. You can do this by adding several, each form a different vendor, to your shopping cart. (On each select ship from China, not ship from USA). If you have setup an account, and the items are in your shopping cart, it shows price for each WITH shipping.
Now becomes easy to select the lowest cost vendor. Buy the one with the lowest total cost and remove the rest from your shopping cart.

The reason for selecting ship from China is the total cost, with shipping, is normally much more if you select the Ship from USA option. For example: This thong https://www.aliexpress.com/item/32997304539.html 
from China it costs $3.72 with shipping, but if you select USA the price drops to 1.42 but the shipping goes up to $7.37 so the price with USA shipping is $8.79.  More than twice the cost of same product shipped from China. 

Each product has a feedback, but they are not very useful, since most people just post five stars when they get the item.  Although it does help to read them. Sometimes someone says somthing useful about sizing,  fit or fabric.

If you are worried, the more important feedback to examine is the vendor. Look towards the top of each listing, there will be a vendor name, something like "OROCOJUCO Collection Store" and then an overall feedback rating for that vendor, like "98.3% Positive feedback".  

However I must admit, having now had a large number of successful transactions, and a few dispute resolutions, I just pick the right item, at the lowest total cost, and order.  Sometimes I get something that is not the size I wanted. I don't file disputes over size, only over shipping or if after one or two extensions of time it never arrives.  If too small I hang the suit sideways in the closet with a weight attached to the other side of the waist, and come back a few months later to see if the waist band loosened up. If too long in the crotch, it goes on the mending pile to be fixed with the sewing machine. Otherwise a miss-fitting suit goes on the SunSplash pile. 

It is a gamble. Most of the time they work out.  If it does not, no worry. Meany cost less than a cup of coffee at Starbucks, and most less than the meal deal at Burger King.  
Just don't flatter yourself: Be realistic about your size, and the fact that most Chinese products are sized WAY smaller. If in any doubt, size up yet another size again.

Cut with a bit more room in front than most Chinese thongs. Good for people who complain that many Chinese thongs don't have enough room in the front. These are suitable for all day wear.

 https://www.aliexpress.com/item/33057404164.html 

An XL is about a US 32 to 33 

 Somewhat transparent so darker colors are going to show through less.   I have the darker blue with black front stripe.

Unusual thong/g-string with some structure to the molded into the front. 

The front panel is thin molded foam rubber, like a thin wet-suit. Sort of similar to the way a molded sleep mask is formed. 

Comfortable under shorts. Might gap a bit on the sides when worn solo, depending on your anatomy.

Sizing is Chinese, so an XL is about a 32 to 33 inch waist.

https://www.aliexpress.com/item/4000336628199.html

For people with extensive thong collections, it's not complete without one of these.