I've always done organic search - it's about time I start on PPC. What's a good site to really cut my teeth on?
Why would you want to spend money on PPC? SEO is much better than PPC! Organic search engine results offer a much high convention rate compared to PPC advertising services.
I totally disagree there, Adwords has always given much higher conversion rates, with SEO you end up ranking for all kinds of crap, not to metion how long it can take to start making money with it.
I would start with adwords. Do a search on google for Adwords Vouchers. There are usually a number kicking around for $100 worth of free ads the first time you use it. It's also by far the highest converting PPC advertising. I do agree though that PPC can be hit or miss so set yourself a budget and stick to it. If it's not working for your site cut your losses and try something else.
If you want to boost your conversion, then PPC can help you that but if you want to have an organic visitors which is good in the long run, then I suggest you to do SEO in your site.
Both PPC and SEO are great. PPC is most costly, but you can start your business immediately. SEO, in contrast, requires more effort and patience, but once it's firmly settled you'll be more than happy.