If your main reason, as you stated on page 1, of buying the bicycle is to lose weight and get in shape. Here's my suggestion:
#1. If you smoke, quit smoking.
#2. Don't spend anything, just start running.
To expand on #2, log your run times. Set a route, consider the route a "lap" and count the total amount of KMs per week. Your objective is to get that number higher as time goes on. Eventually it will become boring as hell and you can just start focusing on speed.
As you start doing this, you will start to develop what is known as a "runners body" which makes you look like an anorexic school girl. To counter this, use the same mentality, get a gym membership, and start level 2 of your training.
I only know of 4 ppl, including myself, that have had the self control and willpower to do the above over the course of 7 years. The result, however, is going from a fat 200 pound 5'6 kid to a ripped 160 pound 5'6 man that club chicks want to feel up. No amount of $$$ you spend will compensate for hard work: as with any other goal in life.