The only thing you listed there that is a requirement for turbine operations is a fire extinguisher (a one time expense). Building and finishing materials are no different for a jet than for any other airplane (scale or sport)...depending on what someone is looking to do, they can use alot of what they already have. Typically those who are serious about getting into jets have been flying for a little while and will have a lot of what is required for flight and basic building and maintanence. My point is that a turbine model doesn't have to break the bank and it can be done such that it doesn't. If you are able to buy a complete package where the materials are supplied, and all you need is some miscellaneous glues and resins to get it together and some paint to get it finished, then you're that much closer at a considerably lower price.

Chris