Ok Abbe here you go and all costs are appox. of course. If you're in the UK, you got to look at around £10 - 12000 to get you rotary licence. (You do get a dispensation for the fixed wing but it's not worth considering in the equation until you go try a whirly and see how you adapt to it). Then you have to build 200hrs PI rotary in order to do the FI course (say around £27000) and then you do the FI course (I'd guess around £7000 ish). After that little lot (lets call it around £45000) you come out with an FI(R). If you're jolly lucky you might get some work from a busy school who will provide the FI cover for you while you're restricted. During this time, the rough going rate for an FI(R) is around the £35 per flying hour mark with nothing for giving ground school tuition. Once you've instructed for 100 hours AND obtained 25 signatures (from your CFI, for supervising 25 solo student flights), you can apply to have the FI(R) restriction lifted. Now, as a fully fledged FI you can charge around £40 per hour.. .. .As you can see it takes an awful lot of instructing to get your money back (and don't let my wife see this post!)! However, the joy and personal satisfaction I get from teaching something that I love (not to mention the entertainment value), has it own intrinsic value and far outweighs the financial considerations of doing it.