When I bought my 15g tank and took my first jump into sand as my substrate I paid $25 (well, my husband paid for it) for the naturals brand natural colored sand at petsmart. I LOVE the look of it, and it seemed as though the maintenance on the 15g was so much easier than that of my older gravel substrate 29g tank. So I eventually decided to do the change and switch the 29g tank from gravel to sand and plant it. Instead of expensive sand, i went to Walmart and got a 50lbs bag of "natural play sand" for $2.97!
I love the look of the sand, my plants LOVE the sand. For moving the sand around in the 29g I have about a dozen trumpet snails, and for the same purpose in my 15g I have 10 black kuhli loaches.
Sand has made my life easier, and my tanks look so much nicer. My bottom dwellers and plants appreciate the sand. My tanks seem healthier with sand verses gravel, as debris doesnt hide in my sand like it can in gravel.
When I need to vacuum the bottom of the tank, I use my old gravel vac and I actually put it right up and over the sand, occasionally even pushing the vac 1/4" into the sand, to get debris, food, and what not up...and I never have but maybe a total of a 1/2 of a teaspoon of sand in the bucket after I do a 30% water change with the gravel vac. (That is with the 29g tank, I approach the 15 gallon differently because it is more heavily planted and the loaches are very active and curious...plus my betta is overly friendly, lol.)
Just wanted to add my 2 cents.
As for plants, I have had the best luck using stem plants (wisteria, moneywort, brazillian pennywort), planted in the sand, as their roots are generally on their stems. I do have other rooted plants that seem to do wonderful in the sand (amazon swords, java ferns, melon sword, corkscrew sword, dwarf SAG, crypt wendtii). The only plants I have had that use to be in the gravel in the 29g are crypt wendtii, and they are now in the sand in the 15g and are doing wonderfully!!!