Where would i progress to buy a straw bale, and how much are they?
Answers: give the local cultivator a visit, he'll trade you one for under a fiver. At one time they'd donate you one, but the prices have risen illogically in the final few years. If you know anyone who keeps horses they may be a polite source of information.
I have individual had a few occasion requiring me to buy a bale of hay. Here in Maryland (USA) I can them at the larger plant nurseries, Home Depot garden department, or a place call Tractor Supply which is a farming supply establishment. They own cost between 5 and 10 dollars. I am not sufficiently knowledgeable just about the different types as mentioned by other posters, I just achieve whatever they own and use it when I am trying to get grass pip to germinate.