Sorry, the government $40 coupon program has been over for many months. The "coupons" were actually like pre-paid debit cards that expired 90 days after issue. If you should happen to have one, or if you find one of these coupons for sale on Craigslist or Ebay, they have expired and they are totally worthless.
That being said, you still have a number of options to find an inexpensive converter box:
Try your local Thrift Store: people often give them to charity when they no longer need them. Garage sales are also a good source, as people upgrade their old TVs.
Walmart, Rite Aid Pharmacy and others often advertize them for sale in the Sunday Newspaper ads. You can use the Auction-Bot section at the bottom of the main Forum list, eBay or your local Craigslist dot org.
If you are near the Canadian or Mexican border and currently receive analog signals from foreign stations, or if you have been receiving a LP analog translator, the Converter Box needs to have a function called "analog pass thru" for it to be able to receive those stations. Many Canadian and Mexican stations are now converting to digital or they will in the near future: Canada changes to digital at the end of this summer.
Make sure you have a proper antenna for it, rabbit ears usually don't work very well. We can help you select the right antenna for your location. If you have any more questions, please ask.
The Digital Stream doesn't have a one screen for all guide like the pal. For each channel you simply hit EPG and it gives you a full listing of PSIP EPG data, and if you select a particular program it gives you the description. It isn't as good as the pal, but it is much better than most converter boxes and digital televisions.