I've used google adwords in the past and had mixed results.
On one hand,it's a free dip in the pool of PPC advertising and can highlight some great suggested keywords etc.
On the other hand, £30 really isn't going to make any kind of dent in the search engine listings with popular words going for +£1 each.
I'd say, have a play around with it and try to learn as much as possible while it's free!
V