If you want to have a successful planted tank the cheapest way possible then do the walstad method. I did my 29 gallon with dirt and this is what I learned: it is definitely a lot of work to start up a dirt tank and get it going but in the long run, less work will have to be done. In my opinion, dirting your tank is the way to go because your plants get everything they need from the dirt and as long as you do it right, your plants will absolutely take off in a dirt tank.
Really, the best advice I can give you is to go YouTube and watch every single video by dustins fish tanks. He knows whats up and he has some great videos. He doesn't inject co2 or have powerful lights and he has great success and it's because of the dirt. Just go watch his videos before you start up the your dirt aquarium and do what he says because He knows what he's talking about.