Amplified indoor antennas are a nuisance. They are ineffectual and create more trouble than they are worth. Amplification is only really useful in fringe reception areas so long as there are no high power transmitters of any kind in the vicinity. I would only use a preamp on an outdoor antenna to overcome loss due a splitter or loss from the coaxial feeder in a fringe reception area and only after precautions were taken (such as filter or trap insertion) to prevent intermodulation with strong local stations.
To give an example of the cheap antennas which have been available, here is a link to the FCC for a citation issued to a resident in Los Angeles. She had a Philips amplified indoor antenna which was self oscillating and interfered with a Verizon cell tower. The resident was issued the citation...
http://www.fcc.gov/eb/FieldNotices/2...-292933A1.html
Remember, poor reception may be due to other factors rather than just low signal level, such as local interference raising the noise floor, and receiver front end intermodulation due to poor receiver agc or selectivity issues.
Cheers,
Terry