I am about to buy tyres and they will be around $1200 and a rollcage for $1750 but that is hopefully absorb into the budget and I miss out on some other things. After doing a few events I thing a rollcage is a necessity for the speeds which you achieve on the track for a prolonged period of time.
I have cut back other luxuries outside of motorsport like lunches and big nights on the booze and put the money to this instead.
Mate you sound just like me, so I know exactly where you're coming from! I've cut my expenses down to allow me to get the car out on the track, because $150-$200 for a track run is more fun than getting drunk and suffering a hangover (IMO!)
Definitely hear you too regarding the rollcage. My g/f has put her foot down and said I have to get one for safety's sake, so who am I to argue!!
Where are you getting a cage for that kind of $$$ and is it a welded or bolt in? 6pt? 8pt?