I thought I'd weigh in on the topic. I started shooting F-Class last year with a Savage 12FVSS, bought used off the ORA in .223. Stock everything, and pre-accutrigger.
I put on the Bushnell 3200 10X40, and a Harris bipod and with some handloads, merrily have been shooting.
Since then, I have changed the trigger to a Rifle Basix Sav 1 - less then $100.00. I shot that this year, even in Ottawa at the early stages of the DCRA shoot.
For next year, I've now changed the tupperware stock to a Boyd's Laminate (again, less then $100.00) but I was able to keep 1 MOA with the handloads before that, and even out to 1000 yards - if I could only read the wind better.
That's not a lot of $$ I've put out when I compare to others, but I think I am pretty close to what some others shoot - and I have a ton of fun!
Looking forward to next year, just got a Tikka T3 in .260 Remington, so give me a bit more edge then before, especially at the longer ranges - and will probably keep this one stock, no mods.
You can spend as much as you like, or a little as you like, if you're serious about winning competitions that is one thing, but if you're serious about shooting, it's another. I think that the challenge is against yourself and learning what you can do, with what you have.