Inside the house storage or garage storage? I've got three stands that hold one bike each; $20-25 apiece. Flexible since they are small. I bought a rack off eBay that looks like one found at the schoolyard; it holds 8 if you squeeze them in. I've got a rack that looks like a small shelf with two arms sticking out; hang the bike on that, put gloves and helmet on shelf.

I also have some racks that hoist the bike up to the ceiling using ropes. Best for long term storage, lot of rope involved. Home Depot sells really big plastic covered hooks that screw into a ceiling joist and hold the bike by the front wheel.

Search eBay, lots of options. Performance, nashbar, REI, etc.