Not just a lot of work. Depending on how it's lowered the cost could be significantly higher. Frame notched? Body drop? Bags?I would sell your truck and buy a 4x4 truck. That is a lot of work for someone that is just getting into 4x4s.
With a solid stock base, you're looking at minimum: Front suspension, rear suspension, transmission, transfer case, front diff/axle, rear axle, wheels/tires, steering, engine... basically a whole truck!
I understand working with what you have, but sometimes what you have just isn't the right thing to work with.
Sell or trade it for a better starting platform. You'll get more out of it as a lowered truck than you will as a half-done "WTF DID I DO?" abandoned project.
OR Do like I did, find another truck, have one lowered and one lifted!
2 trucks means you can always go get parts for the other!