I've been getting into strength training. I bought a power cage, adjustable dumbells, barbell, and 370lb of plate weights all for under $1000 brand new. Working out at home is IMO much easier than working out at the gym. You can get used equipment for even cheaper if you search around.

You can also look at going the crossfit route and get used tracker tires, railroad ties, etc for cheap and throw them around outside.