If you've been thinking about buying an XM or Sirius Radio, now might be a good time to make that purchase as the cost of these radios is now at the lowest point ever.

For example, Crutchfield has the Delphi Roady2 XM Satellite Radio Personal Audio System Package for just $79.99. This package includes Roady2 XM radio with car kit, antenna, and wireless remote and Personal Audio System. As recently as six month ago, the cost of this unit might have been twice as much.

Crutchfield has the hot Delphi SA10113 MyFi XM2Go for $149.99 after $150 savings and a $50 mail-in rebate. This package includes MyFi portable XM receiver, car kit, home kit, earphones, rechargeable battery, belt clip, and wireless remote.

If Sirius is more your thing, you can get the XACT XTR2CK Sirius Satellite Radio and Car Kit from Crutchfield for $29.99 after a $50 mail-in rebate, or the XACT XTR3CK Plug and Play Radio and Car Kit for just $49.99.

Why have these radios gotten so cheap?

The prices of these radios have dropped to these new lows because both companies have adapted the razor and razor blade marketing strategy. This is based on a discovery made years ago by razor manufacturers that you can just about give a man a razor because you will then sell him the blades to use with it for years and years to come.

In other words, XM and Sirius are offering you satellite radios at really cheap prices so they can continue to sell you their services at $12.95 a month for years and years to come.

Stop and think before you buy

Before you buy a satellite radio, you might think about two things. First, that $12.95 a month. On the face of it, that might not seem like much but that's $155 a year this year and every year for years and years. The second thing to think about is HD Radio. This new technology makes AM sound as clear and static-free as today's FM, and FM sound as crystal-clear as if you were listening to a CD. Plus, HD radio is broadcast over the airways and is completely free, just like AM or FM radio.

So before you rush out to buy one of those low-price satellite radios, you might want to stop and think about that $155 a year vs. free.