As someone cursed with curvy hips, I have to say that baggy clothes really help!! I pass as a guy when I wear loose boyish clothing. My only issue is those lumps on my chest...I'm waiting for my binders to arrive in the mail sometime this month. If you want to get a wardrobe without spending too much, you may also want to raid your male friends and family members' closets. Ask them if they have anything they don't want anymore, and see if you find anything you like! Though I may warn you: from my experience, much of their clothes end up with rips and holes here and there. Another alternative would be to visit flea markets or second-hand shops. They usually have a variety of clothes, and you may find a gem hidden in there that someone else didn't want anymore. One's trash is another's treasure.
Oh! And to make sure you get the right size for you, you may want to take your measurements. With your binder on (once you get one), ideally. There are plenty of size converters from FtM and likewise online, so you can figure out your fit from there.
Good luck!