I mixed and matched when i built my home gym. I had a welder build my rack to my design, it cost me $350 compared to over $1000 for most commercially made. Had my bench custom made, cost me $250. Bought my plates from NYBarbells.com, drove up there (5 hours) and picked them up, cost less than shipping.
Also got an ab board, hyper, and standalone bench there. Hunted internet sales for a supported row and a cable pulldown. Got the Texas power bar from EliteFTS, and rubber floor mats from Central Tractor.
Bought the dumbells at dicks, price was the same everywhere, and got plate and dumbell racks at Wal-Mart, they work fine.
Whatever you do, don't get a deadlift jack from new york barbell. Its junk. Spend the extra and get a Forza, its worth your time.
For commercial racks, you could also check out fortified iron, they have some stuff they are now selling.
PM me if you need assistance.