Hey bro, I am almost done with my home gym. At first, I picked up a descent bench from Dick's Sporting Goods; it was like $150 or so. The name was Powerhouse and it had all the basic things you need, just gotta build it; worked well. Now, I have a power cage w/ a lot of other things goin on with it, but that powerhouse type will give you your moneys worth. I tried to look for it online, but couldn't find it.
I bought my dip station from Sears for like $100. I waited for a sale though, works good. As for Db's, I have yet to fulfill my need for all of them yet. I searched ocean to friggin ocean for someone who would give me a deal as I was expecting to buy a lot of hex's, but no good. So, I'm still adding to my library for those. They also sell db handles for olympic weights, but they cost like 70 $bucks or so.
I bought a CAP BB set with a 7-foot olympic bar and 300lbs weight for $100 also from Dick's. They sell extra plates when you need them as well for a descent price, as does Sears.
For when I do deads and things, I got some of that heavy-duty rubber truck matting and have it on the floor. I bought a couple cheap a$$ excercise mats for crunches. I gotta a cheap as$ EZ curl bar, umm....cost like $20. I looked in the paper for awhile and got lucky as fvck and picked up a lat-station/cable station for another $100 bucks.
And for your spotter, I came across a system that is called i think an EZ spotter, works well from what I hear, but never looked much into it. Here's a suggestion, change your workout routine to one rep shy of failure.
Thats all I can think of for now. Just look around a lot in the classified ads, and try to get your equipment from major retailers, and you'll save some ca$h.