Dixon has a good line of regulators, lubricators & oilers. I have some of their stuff and I have been pleased with it. (Dixon is the brand, easily found on the web)
Search on Ebay, you can get Norgren, Parker, Wilkerson or Speedaire for $50 or less easily. I got a NIB Norgren 3/4" Regulator for 250 psi for $40 on Ebay.