One thing that always bothered me about how I grew up was that my mom shopped for me in the most expensive stores, and bought me a ton of things that I just plain didn't like, or didn't work with my tiny frame. So she spent a lot of money on clothes just for me to not end up wearing them. As I've gotten older, I've learned a lot about where to shop and what I like and what looks good on me.
My preferred method of Exploration, but because I apparently forgot how to read:
Consignment Stores
Being overweight has also often been a plague for me, so I don't shop or I shop at consignment stores. I found out there's a really good one a couple miles from me and for exploring my own gender identity, its been my best friend. I think when I splurged and bought clothes for my birthday, I spent 60 or so dollars on myself? Maybe 80? Don't remember. Course for me I was shopping in the mens section, though I did buy two pairs of pants in the female section because none of the mens pants they had fit me. Similar prices across both genders. Also... WALMART! Sounds crazy and cheap, but they really do have some cute stuff for fairly good prices. (Still not as cheap as consignment stores in a lot of cases, but pretty good)
SOOOO as for dressing yourself and what looks good on you? Start with picking out things that you like. Just grab anything and everything off the shelf, (this is what I hate about online shopping is it is much harder to do that) and try them on. One thing I find is that fear overwhelms us when asking what we look good in, and really, often when it comes down to it, what we like is what we look best in. Probably because what we like is what gives us the confidence we need to rock it.
The other idea is, if you're comfortable (or in a store where its a relatively safe place) telling a store clerk you are exploring your gender identity (or hell, you just are wanting to explore crossdressing) they can help you. If not, just say, 'I have a sister/twin/gf that I'm shopping for, and she's built a lot like me. Can you help me pick out clothes that would look good on my body type so I can pick out something for her?' Believe it or not, cismen have to ask for clothes for their siblings/girlfriends a lot, they are more used to it than you think.
Finding your style
(Copying this paragraph so you can skip above section entirely)
SOOOO as for dressing yourself and what looks good on you? Start with picking out things that you like. Just grab anything and everything off the shelf, (this is what I hate about online shopping is it is much harder to do that) and try them on. One thing I find is that fear overwhelms us when asking what we look good in, and really, often when it comes down to it, what we like is what we look best in. Probably because what we like is what gives us the confidence we need to rock it.
One of the great thing about female clothing too, just a tip, is YOU DON'T HAVE TO FRET ABOUT FINDING THE RIGHT PANT LENGTH! They aren't going to go into great detail about leg length, like you would in the mens department. A few brands might, but its actually quite rare. Pants for women come in long, regular, and short/ankle/petite. (Though not always, so if you are tall you may need to make sure you look for brands that have the long leg sizes. Although in my experience when there is no specific length attached, they really do make pants extra long. 'Regular' pants cover my feet. I can wear pants like they have built in shoes hahaha)
Another tip, don't be afraid to layer. Ladies' garment tops are freakishly short half the time, so I end up wearing tank tops with almost everything. (Yeah, I have a freakishly long torso, especially given my 5'2" frame) I make sure to bring this up because as you're exploring still, its not something you might think about.
Where to go online?
AIIIIIIIIIII I just read that you can't do instore shopping, so focus on my clothing tips... Leaving the other stuff in in case someone else finds this thread and needs the information though. I do think there are some consignment stores that you can shop online. If you're not afraid of the Asian Markets, Aliexpress I think it is, is pretty cheaply priced. There are a few others too, but that's the only one I can think of off the top of my head. Also,
Walmart.com still is a good option, and they, like Amazon, also gather items from other sites and will ship to you under their store/site policies.
I don't follow many MTF people on youtube, (Think Stef Sanjati is the only one I follow? I don't remember... Though she does do some makeup tutorials. Don't know if she talks about fashion though) so I can't help you much there. But I do know there are toooooons of makeup videos all over youtube. This sounds weird, but I think even FTM videos where they invite someone to do their makeup for them may even help. There's a few gay youtubers that also do this, and they talk a lot about contouring to shape your face and stuff, but obviously looking up MTF youtubers would help most.
Also anyone here ever wear the show 'What not to wear' back in the day? Hahaha loved that show!
Edit: Bolding sections and titling so you can see where to focus because I'm dumb and didn't realize till halfway through I missed a critical piece in your post