"Don't get cheap on me now." The quality of the tubes in your tube equipment is likely to be significant so consider some NOS from some of the competent venders/individuals on this site. Small signal tubes like the generally interchangeable 6DJ8, 6922, 7308 last a long time...10+ years are possible. When you divide that out, it's worth a consideration. Amperex (older white label) would be a good choice....read "Joe's Tube Lore"
http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html
but, I've heard some good things about the Genalex Gold Lion tubes too.
http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html
but, I've heard some good things about the Genalex Gold Lion tubes too.