There are a number of Campbell-Hausfeld model FP2028 compressors available on eBay for $39.99. This appears to be a good compressor for airbrush use. I’m assuming it has an adjustable output pressure only because the description says suitable for airbrushing and the unit has an ‘airbrush’ label on it.
That particular model does NOT have a built-in regulator.I have seen it at Walmart. You would have to add one. The labeling is misleading. The next model up (About $ 50) has the regulator.