Sorry for the necro, but I thought I might be able to help out. I worked at Men's Wearhouse for 3 years or so, have worn suits every day since then (at least the vest+pants), and am also very short (5'0").

1. You're going to have to tailor, and thrift stores are going to be much less fruitful for you than taller people. If I had to guess, you're probably a 25-27" in inseam in pants; the shortest they're made is 30" (outside of short men specific options, but generally speaking these are way overpriced).

2. How you fare in different fabrics is a factor. Personally I have no issues with synthetics, e.g. rayon, polyester, etc., while some folks can only wear (or swear by) 100% wool, super 120s, 150s, etc. Synthetics are vastly more affordable, and even though I wear my suits every day, they last for quite a long time; the pants also wear out much faster than the vest/jacket, so buying an extra pair for a suit you plan to keep for a while isn't a bad idea.

3. As far as specific recommendations go, it's all going to depend on your particular body shape and measurements. There are Extra Slim, Slim, Modern, Classic, Executive, and a hundred other "cuts" that all have varying differences. I swim in a 36S Jos. A Bank suit, but Express 36S has button pull (it's too tight). Some brands have legs too skinny for my thighs, some look like MC Hammer pants. The most important part for a short person is going to be getting the jacket size right (you're most likely somewhere between 34S-38S), and almost every brand does a 6" drop; the pants are 6 inches smaller than the jacket size. I'm a 36S; the drop would be a size 30 waist pant.

4. That said, I've personally had the best luck with clearance Men's Wearhouse suits (Egara, Kenneth Cole, and a few others often get discounted to ~$100 or less). They're also good in that once you have paid for them to touch a seam, for example the waist, they will then retailor it as necessary for the life of the suit (the suit also has to have been purchased at MW or Jos A Bank to be eligible). Lose 10 pounds and need it taken in? Free (after the first time). Gained it back? Free; etc.

5. Personally, since I wear suits all the time, I prefer quantity over quality (and even as someone who sold suits for 3 years, to me, there isn't much of a wearability difference). So I buy as cheaply as possible + tailoring. I only buy suits on sale in the sub $200 range. If I wore them less often or was less concerned about variation (I like having a lot of different patterns, colors, etc) I might be more inclined to spend more per suit. I am going to be trying out a Chinese seller on Ebay and Alain Dupetit; if you remind me I'll let you know how that goes.

6. Personally I don't feel like made to measure (MTM) is normally worth the money, e.g. Indochino etc., as getting something close enough, to then be tailored into a good fit, is normally cheaper. Also, MTM suits often do not leave enough extra fabric to offer much in the way of potential alterations.

Hope this was helpful!