You can evoke with just yourself.
One of the problems with this is that you have very little to keep yourself focused, so as a new magician, you may have a difficult time with success.
However, there are a number of different practices you can do without most of the ritual materials.
For instance, you can do a scrying evocation, where the only thing you really need is a black mirror or bowl, a light source, and perhaps the sigil of the entity you wish to contact. One of my black mirrors is just a biggish picture frame I got at the dollar store, and I put black paper where the photo would go - seems to work pretty well and is quite inconspicuous. There are lots of threads about scrying around here, the ebook and nearly any of EA’s books should talk about it as well.
You can also do sigil magick or candle magick with a minimum of magickal tools and with stealth.
You could also get into Radionics, go download the ebooks from Uncle Chuckie’s website. That stuff might make you look like a nerd, but it definitely doesn’t look like “black robes and staves” magick. Still very cool stuff, but not nearly so obviously “magickal”. Try to make it look like a craft project and you shouldn’t have a problem. Definitely check out the Psionics Grimmoire.
Similarly, pre-requisite skills such as Astral Projection, meditation, trance-work, energy work, Yoga, Qigong, astral sight/hearing, etc. are all relatively free of props. At most, you need a chair, a notebook, and a few props that aren’t obviously magickal.
Also keep in mind that many of your materials and tools can be very stealthy. A cardboard box or trinket box (with or without a cloth to cover it) can be an altar, I’ve already described simple mirrors, any knife or stick can be your dagger/wand, any cup your chalice. There’s even a thread where necromaster discusses creating a fog machine instead of a brazier for smoke.
As you create ritual tools, keep them nondescript and nonobvious for as long as you must maintain your stealth - and don’t store them together. Keep them in places where the object in question would be kept. If your altar is a trinket box, put some cool rocks in it and put it on the bookshelf. If your dagger looks like a hunting knife, keep it with similar things. Keep your journals and books stored in a secure location where they will not be found, or make your own (false) dust-jackets for them and keep them with other normal books. You get the idea.
I would advise reading ALL of the threads in the newbie forum, as others have asked this question in different ways - there will be a lot of good info for you.
Also, remember, you gotta be 18 to be on this forum… so if you’re not, never admit that you are, haha.