It's not every day that you see an average gamer buying a highend graphics card, such as the Radeon HD 4870 or a Geforce GTX 260/280. These highend graphics cards are really designed for the enthusiast gamer, and will cost a minimum of £180 ($300) and upwards. This is way out of reach for a lot of users and gamers who's on a budget. So, what have manufacturers done to cater for this category of users? 

"Overall, the Radeon HD 4830 is a great all-rounder that offers very good performance and excellent value. Costing around £90.00 ($140), it's cheaper than the HD 4850, but you get performance that nearly matches it. This card is perfect for any gamer who's on a budget."

http://www.cpu3d.com/review/6382-17/ati-radeon-hd-4830-512mb-ddr3-sapphire-vs-his/verdict-and-conclusion.html