Through July 15, 2011, Amtrak is offering 30% bonus when you purchase Amtrak Guest Reward points. Amtrak points can be purchased at $0.0275/point. With this promotion, purchasing points can allow you to ride for cheaper (depending on the fare price). For example, purchasing 5,000 points will give you an additional 1,500 bonus for a total of 6,500 points. A round-trip coach class Northeast ticket is 6,000 points (3,000 one-way), which will cost $137.50 if you purchase the points. In my experience $137.50 for a round-trip ticket in the Northeast can be pretty inexpensive. I have seen prices as low as $49/one-way to as high as $150/one-way.
This past winter, I was able to redeem 3,000 Amtrak points for a one-way trip from Baltimore to NYC. Although 3,000 points can get you all the way from Portland, ME to Virginia Beach, this was a great redemption as the ticket price was over $150/one-way.
Essentially, take a look at your upcoming Amtrak travel (if you have any) and see if it is actually more economical purchasing the points. You actually might find this worthwhile. The T&C state that the bonus points will be posted within 72 hours of completing the transaction.
Click here to purchase points with this promotion.