I strongly recommend running, but it will take a while to build up fitness and even at your tender age that needs to be done slowly… I was getting injured every couple of months until I started doing run/walk – 3 mins run, 1 min walk – with my Garmin watch providing the alerts. I’m almost 60 but I haven’t had a serious injury in the 2 years since I started run/walk, and have now built up sufficient fitness that I have mostly dropped the walking and just run through. When I started running I couldn’t see myself being able to run 5k in under 3o mins, but I now manage it in under 25. I don’t care about my speed, but I find it inspiring to see shorter times as an indicator of increasing fitness.
Last year’s running shoe models can be found for much less than the latest ones. Running costs nothing compared to cycling – you can buy full running kit from Decathlon for the less than the cost of a cassette!
Most of all, have fun – the first 2k are always horrible, but it gets better after that 🙂