You can get all purpose sand at Lowes and Home Depot in there "cement" area.
The all purpose sand is a mix of course and fine sand it also runs about $3.00 for 50 lbs.
Don't use play sand, its too fine and you will have a mess every time it rains.
http://www.homedepot.com/p/Quikrete-50-lb-All-Purpose-Sand-115251/100318450
http://www.lowes.com/pd_98545-286-115251___?productId=3048145&pl=1&Ntt=sand
The all purpose sand is a mix of course and fine sand it also runs about $3.00 for 50 lbs.
Don't use play sand, its too fine and you will have a mess every time it rains.
http://www.homedepot.com/p/Quikrete-50-lb-All-Purpose-Sand-115251/100318450
http://www.lowes.com/pd_98545-286-115251___?productId=3048145&pl=1&Ntt=sand
