Patch your old tubes.

I get punctures all the time.

If you want to avoid them, take these simple steps:

1. Get tyres with some protection. Here, there's even a site dedicated to them: Puncture resistant tyres
2. Check your tyres as often as you can be bothered for little flints or pieces of glass.  Most punctures are caused by small sharp bits that have been working their way into your tyre over a few rides.  Flick them out with a pin/knife/fork/whatever. How often you check will depend on how important it is to you.  If someone you love commutes 13 miles across london to a stressy job, from whom a mid-commute "I've got a puncture" phonecall would cause you plenty of heart-ache, you'll check hers/his every night.
3. Don't ride in the gutter.  Keep your eyes peeled for glass (more and more of it about.  A deliberate campaign?).

Anyway, when you do get a puncture, find the nasty, remove it and change the tube.  Stuff the old tube in your bag and add it to the pile at home.  Don't bother arsing about at the side of the road patching the tube.  It doesn't work well in the rain and once the tube of glue is open it tends to go off before you next use it.

Once every few months, sit down with a box of patches (Rema Tip Top from UK Bikestore at 30p each?), some sand paper, glue and a pump, turn on the afternoon play on Radio 4 and repair them all.

New tube = £4, patch =30p

No brainer.  Can't do it?  Want help?  Email me!