Home gym equipment CAN be as good as the equipment at a gym, but you will have to purchase very expensive equipment and have a place to put it. It is of a professional quality because it's intended use is going to be constant and repetitive.
Home gym fitness equipment can be found in all sorts of places such as yard sales and even craigslist. If you wanted to buy them new you can go to your local Sears to purchase them for a good price.
A good home gym will probably cost, off of a new retail store shelf, about two thousand dollars to the buyer, though they can usually be discounted and cheaper.
Try neighborhood yard sales. There are sure to be a lot of people who purchased equipment for a new year resolution and never followed through! Online, you can always try craigslist or ebay.