New career?

I have two first editions, one of which is worth about what I paid for it (because I only bought it recently) but I happened to mention the other one to our book seller friend last night and my investment of £20 only last year, is now worth over £200!! Pretty cool, huh? So buoyed by what I consider is clear evidence of a new talent, I've just bought two first edition Famous Five books on eBay!
Sadly I don't have lots of money and time to indulge in my new hobby so that's my lot, for a while anyway... I only buy books that I love (Famous Five got me through some difficult periods in my childhood) and I doubt I'll ever have a huge collection but it's kinda fun.