Originally Posted by Roelof

For just 8 dollar you have 100 body clips from Aliexpress, also exhaust rubbers can be found for just 2 dollar per 5 pcs. Screws and other hardware you can buy per 100pcs, going for 50pcs or less may be cheaper but most of the time not that much compared with 100
Hobbyking, Aliexpress and Banggood are also god places to find cheap batteries and tools.

Just do not buy stuff from RC brands if you can find simulair stuf on other markets.

Also own modified engines and mixing own fuel will be very cost saving.