what is the easiest and the cheapest way to cover my great planes trainer 40 kit plane?

Is that cover?

Need more details. Is it open construction? Is it all sheeted? Gas powered, rubber powered, electric? Give us a full description.

Ed S

Go to your LHS and buy some "Ultracote" brand iron-on covering. It costs about $12 per roll and you will need 2 rolls (3 if you want a 3 color scheme). There are cheaper coverings on the market, but you will hate yourself for not getting the better quality.