Here’s the thing. You’re going to be saving money if you climb for at least 10 sessions or so with them.
You can use that knowledge to roughly judge whether investing in climbing shoes is going to be worth it for you.
If you’re a hobbyist, then yes, it’s easily going to be worth it. However, if you’re a rookie and you’re still unsure whether you’re going to take up climbing as even a semi-regular thing, then I’d say wait a while and see.
The truth is, rental shoes aren’t all that bad.
Sure, you can save money by buying your own pair, but there’s one thing that you can’t do without rentals: try a new type of climbing shoe each time, until you find which is the right kind for you.
Alternatively, you could just pick a good starting pair that isn’t going to be causing you any pain. Aggressively shaped shoes are notorious for that, but flatter ones are going to easily be fine if you size them right.
I recommended some excellent, “lowest-possible budget” climbing shoes in this article about how to climb on the cheap. I also talk about some of the other gear you might want to invest in.
As for an actual guide to the different types of climbing shoes and what to look for, Jamie has that covered.
As for the whole “laces vs. Velcro” thing, it’s pretty simple. Laces are more adjustable, while Velcro is easy to slip off if you’re resting between climbs.
If you’re not looking for some budget shoes like I’ve been talking about, want to invest in some quality laced climbing shoes instead, you’ll want to check out Jamie’s post here where he reviews a selection of the best laced climbing shoes out there.