i used a bog standard growbag which was about 15 litres it only cost me a quid (£1) then i got some perlite, that stuff is a quid for only 1 litre but is well worth it
this is what i have done i have mixed a 50/50 mix of them both and then planted with that made up mixture,the perlite helps drainage and airation to the roots so is a must really
i will never do a grow without perlite
cheers hope this helps