Some home powder coat kits use heat lamps instead of an oven. The limiting factor is size of the piece you're doing. To do a complete bike frame would require several high wattage heat lamps and the item needs to be rotated so it heats evenly. DO NOT put powder coated parts in your kitchen oven. It can leave toxic residue.
By the way here's a hint: If you go to a local powder coating shop, ask if they have any large runs of a particular color coming up. Often they will throw your parts in with a large batch. This is usually base colors, black, blue, red, etc. I had a complete Ford rear axle housing done for the cost of materials, about $7.00, because the powder coater was doing lawn furniture in gloss black for a local landscape company. He just threw my housing in with the chairs and tables.
Tom