well if your budget is going to be as cheap as possible... the first thing that i recommend to do is get new tires. Suspension is going to be the most expensive modifications that you will likely be doing so if you want to wait on that i can suggest to get new tires so you can at least get a little bit of traction in the dirt. But really the best thing to do is put in a front and rear suspension. There are many companies out there with different kinds of suspension and long travel kit. You can check out camburg, donahoe, total chaos, ect. for suspension projects. I recommend the BFGoodrich all terrain tires too for the first set that you are going to be putting on your truck. Have you bought a truck yet? If so what kind?