Regular sand is fine, anything that is for Marine or Saltwater tanks should be left for those tanks. I recommend going to your local hardware store. Go to the cement isle and find something called Play Sand, it is $5... for a 50lb bag. This is a lot of sand and a great price at that, you won't get a super unnatural color, but it looks nice and is 100% safe.
You can keep the left overs, use it for another project, donate it to someone, put it in a park, or toss it. It will save you money by throwing the rest out then buying one bag of 2.5lb sand st the petstore.