If you're just maintaining two cars, with no real interest in detailing for others, this is pretty simple. Start with a few basics and build from there, as desired.
POLISHES -
For the casual user I really like Meguiars D300. It may not have the cut of M105 but its much easier to use and leaves a fantastic finish. Depending on your expectations, D300 can be LSP ready; no need for a second polishing step. Buy a 12 oz bottle for $16 or 16 oz for $18. For finishing polish, I like Meguiars M205. It's about the easiest, smoothest, nicest to use light polish available. A D300/M205 combo would be super easy to use and leave a killer finish. You can get a 12 oz sample size for about $11, or see if someone will sell you a small amount.
PADS -
This is where to spend your money. You'll need cutting (compounding) pads and finish polishing pads.... several of each. With D300, the Meguiars Microfiber System pads are best. A pair of 5" cutting pad cost around $20. I also recommend using 3" pads for tight areas. Those will run $12/ pair, plus a 3" backing plate. A couple of black foam finishing pads and a couple of orange foam cutting pads in 5-6" and 3" will round out your inventory. This will burn about 50% of your budget.
WAXES / SEALANTS -
This is where most detailing enthusiasts geek out. Everyone has gone overboard with LSP's at one time or another. Hell, LSP's cause 80% of the internet arguments on detailing forums. We won't hold it against you if you get sucked into the vortex of LSP excess. We've all been there. The truth is, you only need one good product. Like a watch, a man can use only one at a time. I much prefer polymer sealants to waxes. I'm an avid user of Zaino and Blackfire for my LSP. Both are great products; long lasting, high gloss shine, easy to use. I suggest trying to get a small sample of whatever LSP from another user to see if it's something you like. A 4 oz bottle is 6-8 applications. That's all you really need to start. If you find you like it, a larger bottle is around $20-30.
Good luck! Have fun trying new products.