If you want to stay in this hobby cheap, 40 size is the way to go. You can find ARF`s and engines cheap. But for example, my Satio 100 Duster with all servo`s i have around $900.00 investment. The Gas DL- 50, Sundancer, i have around $1,200.00 into it. I paid close to the same price for the 50cc engine as i did for the Satio 100. So when you start getting bigger than a 90 size plane it is almost feasible to fly gas. But if you were on a budget there is nothing wrong with flying 40 size planes. I fact i have one 40 sized electric that i love because it is easy to take it and fly at a soccer field,baseball field and smaller area`s. In fact i was thinking about getting a 40 size Mustang or P-40 glow to train me to fly bigger warbirds later. I wouldn`t feel so bad if i got crazy and bashed one up.