Bike mountable pump

[raceboy]

After getting my 1st road bike puncture yesterday on the way to work, luckily it was a slow one and I limped it in, I think it's time to get a portable pump.
I'd got a puncture repair kit and tools on the bike, but no pump luckily there's a track pump there so fixed at lunch and all was good, but it may well be time to mount a pump to the bike, I know it's against the rules, but I don't like much on my back and there's even a bracket already on the bike, but I bet any new pump doesn't fit in it.
So what's any good without being silly money?

[raceboy]

Bontrager RaceLite 700x23
To be fair they are due a replacement at it's next service at the end of winter, but over winter I don't do that many miles other than the 10 minute commute and it's the first flat I've had in a couple of years.