Unless you have access to true hard driftwood, I do not* suggest DIYing this. Unless its the correct kind, other woods will rot in your tank, or carry gross plant life and creatures.
Many pet stores have woods that can go in for not much. However, the ones in the reptile section are often NOT safe for fully submerged aquatic needs.
You can also look for the skinny, branch/twig like varieties some places sell for cheap, and since theyre so light, the shipping is low. Bobstropicalplants.com has them, but I dont know of others off the top of my head.