You want cheap?… external flash bounced off a white poster board. Better?… add another slave flash on the other side and bounce it as well (more even lighting).

It can be cheap… mirrors and white boards or expensive… snoops, softboxes and backdrops…
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How cheap is cheap? Adorama and B&H have tons of lighting and background stuff, but “cheap” starts at around $500 for the lights alone.

If you have a separate flash, you can bounce it off the wall and ceiling behind you to come close to the umbrella effect. You can buy a new SB600 for $220 and you are well on your way.

Best bang for your buck!