Can I replace my original fog lights with aftermarket led type strip fog lights and what would it cost. Any suggestions for companies that sell them ?

I've seen them on eBay from $19.99 to $225.00

I did this exact procedure on my 2007 SL550. Yes, you can replace the original with LED bulbs. They use the existing bulb socket. The only thing you need to do is to wire in a resistor near the bulb socket (I think it is 10 ohms) for each bulb. These are readily available on Ebay and will probably be less than $10 for a pair. To change the entire configuration - such as replacing the housing with a strip of LED's such as current MB's have - would be terribly expensive and not worth it. If you do not add the resister - you end up with blinking fog lights because the LED's use different voltage.

where would you wire in the resistor may I ask I am trying to do the same thing with my 2006 mercedes benz c230 sport and getting the same issue

I wired mine in just behind the light socket. Any convenient place will work. Important: do not attach the resistor to anything plastic. They generate a lot of heat and could melt what they are attached to. Try a thick plastic tie to hold it in place. That way air can circulate.