Bike Computer

I ended up getting the Garmin 305 just so I can use it for both the bike and run.  I've had it for about 8-9 months now and its worked great, no problems at all.  I got a speed sensor that I attached to the bike so that I can use it when I'm on the trainer.  I've seen that prices have really come down on those things lately so you might be able to find one in your budget.  I'd check online - I've noticed through all my purchases that online is where I've gotten the best deals.  Trisports.com is one of my favorite sites.

x2 on the 305 if your budget is that high.  It will be useful when you can start running again, plus it makes logging a snap.

Costco has them for about $150 right now

X3 on the 305 I got muine for just under $150 with the heart rate strap on Amazon.com for less than $200 I added the cadence monitor and quick release adapters.

I also just use my 305, the only thing missing out of the box is a cadence sensor

I prefer old school as my base setup. I just need cadence, MPH, total miles, time and average MPH. The Garmin stuff is a great add on for more detail, but it has to be charged, remembered, etc. You should be able to get a bike computer for $50 to $65 that does all the needed stuff. Unlike the Garmin, it's always on the bike and the battery will last from two to six years depending on the model of computer.

After you get the basic computer in place, then it's Garmin time.

My first one was a cheapo $4 junk from evilbay.  I didn't really buy it for biking purpose.  I used for maybe 2 - 3 ride before it stop working. 

I got a $20 Schwinn from dept store with the very basic feature.  It work flawlessly. 
Although it is only a basic computer but there are more features I don't need.  All I need is the speedo, average speed and time. 

If there is anything else I am asking for it would be cadence.

I also have the FR305.  But the features that I had on my other computer (that I found essential) were:

Speed
Distance
Time
Cadence

I like having the 305 for HR and the gps mapping is so easy to upload here on BT.  If you are in the $150 market - I'd go with the  FR305, you would then need to add in the quick release (velcro wrist watch and the attachment for your bike).  The Cadence and speed sensor (speed sensor is for indoor training but it is included with the cadence setup).  So the downside to the FR305 is that you'll probably end up buying more extra stuff, but if I remember right, should be less than $100.