I ran a C on a 6' back mower last year, and burned it up. unless you yard is long and narrow you'll find it almost impossible to do the corners, so you'll need a rider anyway. C's don't turn well with the back mower, and won't want to pick one up on the 3 point. They don't have enough power to be happy with over 5' of mower, and the factory hydraulics are marginal for a 3 point. A nice C is about $1500 (unless it's wide front, add $250), a perfect one is $2500, a beater is $800-1000. Adding a 3 point (never installed at the factory) runs $350-450.
I also have a B with a 5' Woods belly mower, that works great. THese mowers are about $2000. I still use a rider to do edges and corners. I'm mowing 5 acres of flat and straight lawn - I bought a 18 horse 48" rider for edging, a 6' finish mower for the main body, and a 34HP tractor to drive it, because the B/C gearing was too slow in first and skipped spots in 2nd.
From personal experience - for 1 acre, buy a 48" hydrostat mower and be happy.
Cultivator - $75 if all there
Mounted sickle mower - $250 operable
Pull behind - $100-$500 depending on condition and if finish or "brush hog"
Plow - $100