I've not found the soil test kits from garden centers to be very reliable and they do not provide adequate information. The pH test does not tell you if you need Calcitic or Dolomitic limestone and most often, for me, the result is not accurate. The test often shows the pH of vinegar and chlorine to be the same and they should not be.
Your states Cooperative Extension Service may provide, relatively inexpensively, soil testing that is good and with recommendations to correct any deficiencies.

What he said.

"I'm on a tight budget."

Then the best one is NO test kit at all. :)

Have you even tryed growing in your soil yet?

I just bought this house. It had some roses and a lemon tree going, but I wanted to get an idea of what I'm working with.

A soil test done by Michigan State University through the Cooperative Extension Service office is $13.00 per sample, others are less, some more. With that soil test you get information about what is going on in your soil and how to correct any deficiencies. A good, reliable soil test cn help save you money by showing you that you may not need to apply certain materials, or maybe not in the amount someone tells you, one reason why many farmers rely on them to guide what they apply to their fields.
in addition to that soil test these simple soil tests can also help.
1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains� too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer your soil will smell.

5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.

Check with your states Agricultural School, the one with the Cooperative Extension Service offices, to find out about having that good, reliable soil test done.