I think tomatoes are most popular plant being grown in thehome vegetable garden. Tomatoes require fertilization at certain times of theirgrowth depending on the type on nutrients being available in the soil. And Ibelieve high quality Compost is best for plants.
According to the University of Missouri extension service, tomatoes need "a fertilizer low in nitrogen (N), high in phosphorous (P) and medium to high in potassium (K). Among the best analyses for tomatoes are 8-32-16 and 6-24-24."
I use worm castings and Tomato Tone by Espoma. Stay away from chemical fertilizers as much as possible so as not to build up too much salts. High nitrogen ferts will encourage leaf growth and not so much fruit.
A cheap and good fertilizer for plants of any kind u wont believe it but after boiling potatoes or pasta save the starch infused water let it cool completely and then water your plants they love the starch. Cheap fertilizer and best of all no chemicals.