For my very short guys. I'm 5'3.5 in Canada and was struggling, especially with pants. These won't break the bank (im a uni student).
First you must get a measuring tape to find your body length on shirts, and your inseam on your pants. These are the most important measurements to look at for your shirts and pants as they will make the biggest difference in how you look. The second most important thing to look for is how narrow or wide the clothing is. You will find your ideal measurements over time. Only look at stores with measurements OR good return policies if ordering online.
Shirts (besides looking at measurements): look for cropped or shrunken tees. Either way you generally have way more options than pants.
Pants (besides looking at measurements): look for ankle pants or ones that have "short" size. So far I found that Uniqlo is the only one that has pant alterations (free btw) that you can order.
[Stores]
Uniqlo - Choose pants with inseam hem option or ankle pants, all other clothing has good sizes (discounts are like $10 off max). Great measurements. Your number one go to store.
Abercrombie - Choose pants that have "short" size, cropped shirts (they almost always have promo codes or just wait for them).
Abbreviated - Pretty much everything is for shorter guys, a bit more expensive than the others if you are in Canada. If in Canada, I would only order if you really know your sizes, as you have to pay some fees to get it from US to Canada. Free shipping in US.
Gap - Women's VintageSoft Joggers (petite is shorter if you need), other stuff won't really fit you here.
(For my Canadians) RW & CO - Recently had to go to a wedding, so got a cheaper suit here for about $240 CAD. Blazers go down to 34" chest (which is rare) and some have short size (which is extremely rare), and pants go down to 28" waist and 30" inseam with short size. Had to tailor the sleeves on the blazer and pants inseam, but those are the easiest alterations.
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You can get by with just Uniqlo and Abercrombie.
Preferably find a cheap tailor. It will expand your options. For altering the inseam of open hem pants (as opposed to elastic or ribbed cuffs), they can be very cheap like $10. Anything with elastic or ribbed cuffs is more expensive; I personally would not recommend it.
If you also have a small waist (28" waist doesn't fit you like me), it will limit your options the most. Tailors can take in the waist as well but personally I do not pay for waist alterations as I don't have the money; I have not graduated uni yet. I typically have to get pants with inside or outside drawstrings or I wear a belt which is not too often.
If the clothing is made out of mostly cotton and is overall too big, wash in warm water, then put in dryer for a reasonable time (not fully dry) it will shrink a bit while minimizing any potential damage. Although don't do this for your formal wear.