You are what you eat. You eat cheap and greasy food you will look like that. Your probably on the thinner side so fat and carbs may not be an issue. Incorporate protein in every meal and invest in some whey protein and just keep in the mind those aren't meal replacements, eating solids is the best way to go. Canned tuna and chicken aren't expensive at all, there are days where Safeway and other grocery stores go on sale with $.99 a lb for chicken breast, as well as $2.00 a lb for some chop. Low in carbs and fat and packed with protein.
If your scared of eating unhealthy its really your choice, I mean if you don't want to eat unhealthy just cook the night before and make extra. Prepack your meals for the next day as well as your shakes. I did that for a year now and its just grown on me. Eat breakfast at home, pack a lunch and my shake then a couple of snacks.
Becoming a "bodybuilder" is hard work and takes years of training, you won't become a "bodybuilder" over night. Do a little more reading and research, and aim for strength and the size will come. Well good luck with ya