When I started out I wore what was at hand and liked in my sisters or mums wardrobes. When I started to buy it was from mail order ( No internet) and from charity shops. I had an idea in my head what I wanted to wear and some of it didn’t suit. I used Miss Trial and Mrs Error in creating a look that suited me and knew my sizing well. I took a small measure with me. I had a keen eye looking at what ladies were wearing and hanging on the rails in many shops, eventually I found my style.
Trying things on in shops came later for me when I dressed to go out. If you don’t want new then charity shops are a great source of bargains and do have changing rooms. The big supermarkets have some great bargains on the sale rail and have changing rooms too. I think shops are more relaxed about males trying on womens clothes, you could always go in the male ones. Eventually you will find the items that will suit and buying gets easier, even buying without trying. E bay became a source for me and there are great bargains but only buy if they have proper sizing and measurements as one sellers 12 could be a 16!