It varies vitamin to vitamin. Some companies are great quality other suck horribly. Here's Kabuki's list of good vitamin choices from Sherdog's nutrition forum:
1) Balanced Essentials from Heaven Sent - Here you have a formula made from whole food sources that comes in liquid form and the taste isn't excruciating. With liquid you get the better absorbancy, and the whole food source mean this would be like what you SHOULD get from Vitamin content of all your food, but don't because food in the US SUCKS.
2) Sea Essentials by Heaven Sent - This was their first formula. People had discrepencies because it doesn't list the precise values of Vitamins it contains. But Heaven Sent aren't to blame for this. The FDA is. Because of the nature of the blend (Sea Vegetable preparation) the numbers vary slightly from batch-to-batch. The FDA said if they can't make it precise, they can't put numbers. But the antipoxidant and mineral properties of this are very good. And it was the Sea Essentials that I took and never, EVER got sick. I switched to Mega Men this year, and got my first cold in 3 years.
3) GNC Ultra Mega Green - Most Americans just do not get enough greens. Plain and simple. This is another Vitamin with whole food nutrients in it. But the drawback is these things are GIGANTIC. Not Horse pills, Elephant pills. And suggested use is 3 times per day (to supplement veggies with your meal), but like Mick states I think this is a bit of overkill. 2 per day in the morning should do.
4) Garden of Life's Living Multi - Notice a theme here? I hate the idea of purely synthetic vitamins. If you can score a good one with whole food nutrients you're going to find the health benefits a bit better. This is a good one. Garden of Life is a good line of things anyway, very reputable.
5) Nature's Plus - Source of Life. The customers who use this never, ever consider taking another one. And yet again another whole food source Vitamin.
Now, cheap? What will suffice? Well you have GNC's Mega Men, Twinlab's Daily Two, Solgar has a decent multi (Solgar is actually an excellent line but they tend to be pricey as well as they come from Japan.)
Another excellent choice is Greens+.