There are always lesser expensive options out there, such as Elite screens, but I'm really unsure of their quality, and the one that I saw had horrible sparkles on the screen which really turned me off to the company.
The MSRP of Carada - their online pricing - is less than most companies pay, at cost, for the competition, which is a significant sign of how much less they are than the big manufacturuers, but the reviews of their product, with customer testimonials is the real proof of their quality.
The best cheaper solutions can be neither for many people.
1. Goo: Sorry, I'm not a fan of painted walls. You can go with a piece of board that you paint, that may be better, but painting your walls is a good way to ask for a nail to pop and ruin all of your effort. Forget Goo altogether and going with decent paints makes more sense, but still, the same issue.
2. Build a screen... I did this once, and it worked great. They look very good... every bit as good as my motorized Draper screen. But, it was about a 10 hour effort all said and done and my time is worth more than that. Not sure how busy you are, but if you aren't up for it, then forget it.
Most of all - none of these are portable solutions. If you intend to move, or change things, then there is no solution that these offer. You either leave the wall with the Goo on it, or you break down the screen completely... and it's basically broken. With the professional screen, you disassemble it, wrap it up carefully, and put it back together wherever you want it later on.
Smart call with the Carada! Pure grade A quality!