Nowadays, it is really hard to imagine a Saturday on Twitter following the football without one word popping up time and time again, "Acca". Short for an accumulator, this is a bet of many normal single bets with the winnings of each leg rolled onto the next bet. The number of selections involved can range from two (known as a double) up to any number you want.
The best betting sites for accumulators are going to be all-round "best betting sites" with a number of strings to their Bow, great odds, lots of betting markets, etc, etc. A few extra things to consider are what are the min stake amounts, what are the max winnings per bet, and are there any bonuses or Free bet offers to do with Accumulator bets, because these are things you will be interested in.