A whole airbrush/spray paint booth for $3?! Yep! (well, mostly 😉) 

(somewhat of a WIP, will update with more images once my own build is complete!)

I wanted a spray booth for working on tabletop gaming miniatures, but didn't want to spend between $75 and $200 for a few fans, a filter, and some plastic that'll instantly get covered in paint. I'd been using an old cardboard box, but wanted an upgrade of some sort without spending tens of dollars. Then I realized, the foam board used for school posters and DIY RC Aircraft alike is perfect for the job!

The completed spray booth is 20" wide, 15" tall, and 15" deep, with a 20"x10" top “shelf” (that can't hold that much, it is foam board!) 

Now, when I claim this whole spray booth can cost $3, it's not (just) clickbait! If you don't need fans/filtered ventilation, you can easily build this whole project for that cost, as all it takes is 2 20"x30" foam core poster boards (commonly found at the dollar store for ~$1 each), some hot glue, a long( ≥18") straight edge/measuring device, a knife, and an hour of time. If you take this path, please only use this outside/in a very well ventilated area! Paint fumes aren't something you should breathe :) 

That being said, it isn't a super useful spray booth without ventilation, so the intended build uses mounts for a common, cheap “Blue and White” airbrush/paint booth filter (see BOM for details), and uses SGV's Dual 120mm Fan Mount mount (or BYO, if you can screw through and mount 2 fans on the back of the booth behind the filter, you can use whatever you want!): https://www.printables.com/model/225266

If you're going to use this inside, I'd highly recommenced also printing something to direct and filter the fumes a bit more, also attaching it to some ducting to route out a window. This model is a great example (might not work with the above mount!) https://www.printables.com/model/595603-dual-120mm-fan-fume-extractor-w-carbon-air-filter

All in all, there are a few variations on the BOM for this:
(All printed parts were printed at 15% infill w/ 2 Walls, and should fit on a Bambu Lab X1 no problem - I printed them in Polylite PETG, but any PLA should work fine, too) 

Fancy Paint Collecting Box  - $3

• 2 x 20" by 30" Foam Core Poster Boards - $1ea (Find at local dollar stores/Walmart in USA)
• Hot Glue - ≤$1 
• Required Tools (Razor/Knife, Hot Glue Gun, Pencil, Tape Measure OR yardstick)
• Recommended Tools ( ≥18" Straight Edge, Carpenter's Square, Small heavy objects to brace parts while gluing) 

I own fans and want to use them! - $10-15

• 2 x 20" by 30" Foam Core Poster Boards - $1ea (Find at local dollar stores/Walmart in USA)
• Hot Glue - ≤$1 
• 2 x 120mm PC Fans (High static pressure is optimal, since going through a filter) - $0
• 1 x Fan Splitter Y-Cable - if you own fans you probably have one - $0
• 1 x Fan Speed Controller (Note I haven't tried these myself, its not on me if they catch fire or otherwise destroy/hurt something, or if they don't work)
  • 12V 4 Pin PWM Fans (With Speed Control)- ~$5 - https://www.aliexpress.us/item/3256806034574224.html
  • 12V 3 or 4 pin Fans (without speed control) - $2 - https://www.aliexpress.us/item/3256804409986499.html
  • Some other power/speed control solution for 2 x 120mm fans you own
• 16" x 0.875" x 7.3" (~185 x ~22 x ~405mm) Piece Paint Booth Filter - $5 (cheaper in multi packs) https://www.aliexpress.us/item/3256804893984496.html (or Amazon: https://www.amazon.com/dp/B0CYGJ4KMN )
• Printed Filter Holders (Left and Right) - (~110g filament @ 2 walls w/ 15% infill)
• Printed 2x120mm Fan Bracket - (~78g filament @ 2 walls w/ 15% infill)
• Required Tools (Razor/Knife, Hot Glue Gun, Pencil, Tape Measure OR yardstick)
• Recommended Tools ( ≥18" Straight Edge, Carpenter's Square, Small heavy objects to brace parts while gluing) 

I don't own fans and want to us them! - $20-25

• 2 x 20" by 30" Foam Core Poster Boards - $1ea (Find at local dollar stores/Walmart in USA)
• Hot Glue - ≤$1 
• 2 x 120mm PC Fans w/ Power & Speed Controller - $14 - https://www.aliexpress.us/item/3256805984362584.html (or Amazon  https://www.amazon.com/gp/product/B08CVDJD7Y )
• 16" x 0.875" x 7.3" (~185mm x ~22mm x ~405mm) Piece Paint Booth Filter - $5 (cheaper in multi packs) https://www.aliexpress.us/item/3256804893984496.html (or Amazon: https://www.amazon.com/dp/B0CYGJ4KMN )
• Printed Filter Holders (Left and Right) - (~110g filament @ 2 walls w/ 15% infill)
• Printed 2x120mm Fan Bracket - (~78g filament @ 2 walls w/ 15% infill)
• Required Tools (Razor/Knife, Hot Glue Gun, Pencil, Tape Measure OR yardstick)
• Recommended Tools ( ≥18" Straight Edge, Carpenter's Square, Small heavy objects to brace parts while gluing) 

All in all, this can hopefully provide a low cost option for anyone looking to airbrush/spray paint stuff on a budget. I've included all the design files - done in Autodesk Inventor 2023 - here for anyone to modify for their own purposes (or generally improve), but please keep in mind this is non-commercial and share-alike, it's meant to be open and accessible! 

Assembly/Exploded View Video: