I got this one from HF - 3 gal. 1/3 HP 100 PSI Oilless Pancake Air Compressor
Very lightweight, plenty of power to blow out the water lines and it's got enough power to bring my rear tires up to 80psi (takes a little while, but not really an issue).
It's small and light enough that I carry it in the motorhome's storage compartment.
If you look for HF coupons you can buy it for $39, or if you have a 20% off coupon you can get it for around $47.
2015 Forester 2301 - Chevy
Skip & Deb - Denmark, ME & Delray Beach, FL