The last canon power levels we got for each character were these.
Yamcha: 1,480 (Saiyan Saga)
Chiaotzu: 610 (Saiyan Saga)
Now based on certain feats the characters can do. Goku could pick a car up at the start of DB with a power level of 10. A farmer with a shotgun has a power level of 5, and Korin a power level of 190, Master Roshi 139.
So for feats we have.
Lifting Cars: 10
Destroying the Moon: 139
Chances are Videl's power level was probably around 7-8 or so, she can beat people with guns, but can't lift cars. Her flying is irrelevant since its just Ki control.