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There are many types of exercise equipment and the cheapest would be home exercise equipment. If you are on a budget and you have room I would get something like the Body Solid GDIB46LP Olympic Bench Package, but if you don't need the pull down then I'd get something like the Body Champ Olympic Weight Bench with Preacher Curl, Leg Developer and Crunch Handle (a lot cheaper too).
If you're not into building muscle mass but you want to stay toned then I would go with the Total Gym XLS, which I talk about a bit in my About page. I'm not that fond of the Total Gym, but it will keep you toned. There are a lot of home gyms that can do that, but I think the Total Gym is probably the best price and quality wise.
Yet, If you can find the Total Gym XL I suggest you get that one because it would be cheaper than the XLS, plus it is basically the same and it is sturdier.
The only home gym that I think might be better than that Total Gym and you might even be able to build muscle with would be the Bowflex. I have never tried one because they are to pricy, but if you want one of them I wouldn't go with one of the cheapest ones, nor the most expensive. If I could afford one I would get the Bowflex Extreme 2SE Home Gym.
But there is no home gym that can outdo free weights.