You can get a good, VR capable machine with room for future upgrades for between $700 and $900 easy. Pick up a cheap monitor from goodwill for $25, buy a Rift S for $400, and a $250 G920. If you can't afford the Rift S yet, just get a nice 60 Hz monitor to tide you over for a couple hundred. Buy Assetto Corsa for cheap and play around with it for a few months. You'll have a ball for $1000 to $1500 starting from scratch and have so many options, both in simracing and outside it, then can decide how much you like it and look into iRacing.
Edit: I bought this for $650 when it went on sale in June, and paid another $40 for another 16 GB of RAM. It runs VR just fine on medium settings.