If you want to get studio quality results without all of the expensive lighting equipment, there is a way, but you have to get creative. If you're willing to get resourceful and take time to learn about lighting then here are some ways you can get great studio-like images using what you have.
One of the keys to studio lighting is "bouncing" the light off of reflectors or umbrellas to create full, soft, and even light. Although this can be tricky to do without multiple light sources, you can create the same effect by making your own reflectors. Lots of things will work to help soften the shadows that are created when you're only using a single light source such as the sun. For example, you can use a white sheet, a large piece of poster board or even a large piece of Styrofoam.
Use Backdrops Creatively
You may not be able to have a large selection of photo backdrops like in a professional studio, but that doesn't mean you can't have fun creating one of your own. You can use bed sheets for basic colors and then if you want to get creative you can always use paint to create a pattern or add color. The best thing to do is hang your backdrops on the opposite side of a big window or a large bright opening (like a garage door opening) and it will be like you're using a fill light pointed directly at the subject.
Get Out the Paint Brush
Whenever you go to shoot, always remember that all surfaces either reflect or absorb light so keep this in mind especially when designing a room for taking pictures. If having a lot of lights in the room isn't an option, then you should consider painting the walls and floor white. The white color of the walls will help bounce light around the room for a more even look.
Control the Flash
A direct flash will often make the subject have harsh shadows or look shallow but if used correctly it can be a great lighting tool. Whenever you can, try to bounce it off surfaces surrounding your subject and only use it to fill in shadows from the front. Think about it this way - if the image you are building looks like you won't need a flash, that's a perfect time to use one for additional fill.
Watch Your Time
Light looks different at different times of day. If you use your homemade reflectors to soften the shadows and use your backdrop facing towards the early morning light, you'll be happily surprised at the great results you'll get. Try shooting pictures at different times of the day to see how the light impacts your images and then always book your studio shoots at the best possible lighting time.
When working with lighting, always remember that studio lights were designed primarily to mimic the sun because of the desirable effect of natural light. If you know how to properly control light and use it to your advantage, then there is no reason why you can't create images that look like they were shot in a top notch photo studio. If you have a little creativity and the will to do it, you can easily create your own inexpensive makeshift studio with just a little effort. When you're all done shooting, really the only important thing is the quality of your pictures - the method is secondary.