I haven't used a slant/ slope so cannot offer any advise but what I would suggest for something simpler is you can get a decent yeast.. go for a liquid English yeast and you can step up and make huge starters and split it.. you can harvest it and get many many uses out of it..
Or you could harvest from a bottle conditioned ale, I have done the shepherds neame and am doing the Wye valley (Butty Bach) now.
MyQul made a great guide here
http://www.thehomebrewforum.co.uk/showthread.php?t=53567&highlight=culture
It does work, it requires a bit of effort and onvolvement but the results are going to be cheaper than bulk buying s04 and ultimatley the beer is going to be better.