I think this belongs in the "orlando" forum.
If you want golf stuff, you could drive the 1 hour from Lake Mary (up/east I-4, north I-95) to the Daytona Beach area (LPGA blvd) where there is the official golf stores. There's also quite a bit of factory outlets on I-drive (tourist area), also 1 hour from Lake Mary (down/west I-4 to near Disney).
As for electronics, there are Circuit City, Best Buy, CompUSA, OfficeMax/Depot, Staples, etc. Not sure if you wanted a specialty store or just one of those general stores.
If you're staying in Lake Mary, Lake Mary Blvd at Lake Emma (near I-4) has many shops, including Kmart/Albertsons and solar-powered BP Connect station. If you drive for 5 minutes, in Heathrow, near I-4 (exit at SR 46a, go west) on SR46a there's a new Colonial TownCenter which is a more upscale shopping area (with the newest and best Albertsons grocery store I've ever seen), but Lake mary Blvd is pretty upscale already.
Have fun in Orlando!