If you've got non-VTEC sohc you have more camshaft options and they are cheaper too. But more companies are on the bandwagon with sohc VTEC now, like those above. Also Gude, Crane, JG make them or have them made for them.
On a VTEC properly tuned with I/H/E, a good cam and gear can net you anywhere from 8-20 hp depending on the grind. But the high-hp grinds will generally require a valvespring/retainer kit which will run you about $250, maybe more.