Message Display "Check Coolant Level" & Leakage

Every now and then I got the message "Check Coolant Level" and finally looked at the reservoir and it looks pretty dried up in there & little crust that is formed near the cap. Also, I noticed there was some sort of a leak under the car (almost in the middle) and it seemed like it was the coolant, light bluish with sticky feel to it. Its not directly under the reservoir nor near the tank, somewhere in the middle of the car.

If I take it to the stealership, what could be the cost? And, if I need to add coolant, could it be any 50/50 anti-freeze/water from AutoShop/Pepboys or specific part type?

Thanks for the input in advance.