Hello Redd,
I couldn't find a GC280 camera, but if it takes a compact flash card, or a SD size card, you won't find anything that small anymore, 20mb. Unless you mean Gb, gigabytes? And some of these, 16Gb or 32 Gb get pricey. So I would imagine if you have an older camera and need more memory, go to any of the big stores, like Wal-Mart,Sam's,Costco. I just bought 2-4Gb compact flash crdas for about $30. Do some research before and make sure your older camera can handle these bigger and faster cards,
Rich Franco
www.richfrancophotography.com