Its linked in the post :)

https://www.amazon.com/Optoma-X600-Lumen-Network-Projector/dp/B00GGGQHHC

I used this one for two small tours on the east coast with no problem. Stacking 2 of them has been perfect for dealing with in house lighting issues

For under 300: save up. These days you want something 3k or brighten in lumens, I recommend 5K or more for anything with house lighting/small venue. I use a 6k as my regular. Laser or DLP projectors are going to give you the best contrast and darkest blacks while LCD will not. If you're doing any sort Trompe-l'œil geometric illusions you want the darkest blacks.

This is what I use and I wouldn't recommend anything less if you're trying to get paid gigs.

If you are looking to only do stuff indoors with no ambient lighting to just study projection mapping then something 3K lumens will be fine but I would say anything less than $300 is going to cost you as an investment in the long run.

EDIT: Also check out 6 month no interest financing from Amazon Credit Card/Paypal. I've used this successfully to make big purchase and split it out so I wasnt at risk. If you miss a payment though you end up paying full interest. I just make sure I pay off and watch my balance.