"I want to keep the project under $100". I understand, we all want to do the right things and on a budget. Of course wall and ceiling insulation would be the #1 suggestion in my book, we'll wait on that one. Trees are a great idea, but they cost and have to grow. Without knowing if you have windows, or some manner to exhaust the air, I believe those fans you want will only move hot air around, sorry. I built a 24 x 36 unattached garage with 10' ceilings, in 1996 on a "worn shoe-string" budget, and it got hot in there as I was finishing the inside in August. I have windows, you didn't mention whether you had any or not. I started out with those $10 (back then) box fans in windows to push air in one side and pull out or the other, that worked better than nothing. The I cut a hole in the ceiling just a little smaller than one of those box fans, I placed a box fan lying over the hole, I left the switch on #3, plugged the cord into an extension cord so I could plug it up and unplug it, and that helped a bunch. I know it's not recommended, but it was temporary. Some time later I bought a whole house fan like you put in the ceiling in your home to replace it, what a difference that made. I had enough soffit vents and two gable vents for discharge. Now all walls and ceiling are insulated, I changed the big shop doors to insulated doors, as my shop faces south. It has been over 100º here for three weeks now, I can go in the shop with the doors closed, the ceiling fan on, and it is tolerable, when it's that hot out there's only so much you can do. Good Luck, David