Because it is a smaller tank you can go to a LFS and just get a 5LB bag of aquariam sand, it is about $5.00. I just used one bag myself to change from gravel because my cat fish was eating the gravel. It was a ten gal so you only need one bag to get about a inch and half of covage , if you want it deeper just get two bags and save the rest of the second bag for when you vacume the top layer of the sand off.
pool filter sand is an cheaper alternative if you were going to do a 180 gal tank, i have play sand in my 180 gal tank and aquariam sand in my 10 gal and i like the way the aquariam sand is in the water alot better but it is a whole lot money to do 5LB bags on a 180 gal, the aquariam sand is better to because when the fish fluster the sand it dosnt float around like the finer sands like pool filter and play sand
If you do plan on doing another tank sooner or later or a bigger tank down the road soon, I would go ahead and spend the $4 and just get a bag of play sand at Home Depot. You can always save the left over for later or to replenish any sand that comes out when you clean the tank.