Kentmere and Fomapan might be on the cheap side, but they are good films. Foma has improved production quality and a new base film in the last year. You can find Fomapan 100 at £2.60 a roll with Silverprint and for Kentmere the cheapest is around £32.00 for a pack of 10 rolls with Discount Films direct. They are good and reputable companies operating for many years.
Pete, Amateur only means you don't make money out of it. It doesn't mean you aren't an artist or a knowledgeable chap!
Enjoy your photography!
"Amateur" comes from a Latin root meaning "love". It means you do it because you love to. It says nothing about level of skill, etc.