I recently began to dress and have gone through everything that you are now experiencing. A couple more tips that I can give you..
In respect to clothes...
Goodwill or other thrift shops are a great ace to start. The prices are very cheap. I also used an early visit to figure out my sizes. You shouldn't worry about using the changing rooms. No one in the store cares.
Also shopping in other stores is very easy. I've bought make up in Sephora and the local drug store. The SA's in Sephora were very helpful and helped me pick out the right shades.
I've also bought bras and panties in both lingerie shops and department stores. When you get a set of forms Soma or VS will be helpful I fitting you for a correct size bra.
I basically started slowly and continued to add more items over time.
Enjoy the journey. It's been a wonderful life changing experience.
