Is it compatible?

no sir. that motherboard is full size ATX, that case will accept mATX, mini Itx and DTX motherboards only. too many expansion slots.
look for a board with 4 expansion slots on the mATX form factor

also from best buy that should work for you based on the original motherboard specs
http://www.bestbuy.com/site/asus-m5a78l-m-usb3-desktop-motherboard-multi/1309612970.p?id=mp1309612970&skuId=1309612970
http://www.bestbuy.com/site/asus-desktop-motherboard-amd-760g-chipset-socket-am3-multi/1314222683.p?id=mp1314222683&skuId=1314222683
not advocating either for purchase, just examples of the size that will fit in your case
 


What would be the best but cheapest am3+ motherboard that would fit in my case?