Around here, I find larger tanks used at thrift stores, garage sales, and flea markets for around $20. If it has a screen lid, it might go to $50. That's used, of course.
The snakes, I wouldn't think would cost $150 each, but that of course depends on whether YOU feel they are worth that to you. I paid about $90 for my first normal male from a reptile store, and I still consider him a bargain. The latest normal male I paid money for(in a group where I couldn't pick out the ones I wanted) was about $40.
Check out rescues, craigslist, and the like locally for you. But if you really like the snakes in the ad, it's your decision. Just be sure to quarentine them from any other snakes you already have.
Good luck