I have used LAST products ever since they started (locally here in the SF Bay Area) 20 or more years ago. Mostly it has been their vinyl LP preservative (Last Formula 2) which is very popular among vinylphiles. However, I have been using the LAST Formula 9 (Tape Head treatment) and Formula 10 (Tape Preservative) ever since they were introduced (don't remember how long ago - I think 15 or more years). The Last Formula 9 (comes in a 1/4 oz bottle with brush) (now $41 a bottle) should last a person a lifetime of brushing on tape heads (if you don't have 20 machines). My bottle is probably 15 years old and is still almost full. The Formula 10 does get used up. It is most economical in the big size ($300 for 16 oz.) My most recent bottle has been about 1/3 used (6 oz) treating about 150 tapes. I have a total of about 500 tapes and have treated all of them, so over the years I have used several bottles (mostly purchased in the 2 oz size currently $49.50). So I would say that using Formula 10, you get about 25 tapes per oz. or at the retail price, about $1 per tape. One normal treatment is supposed to last forever and treat up to 1800 ft. I haven't done AB comparisons, but I see that the Formula 10 cleans the tapes of tape flakes and dust and my heads don't need cleaning very much. It also reduces or eliminates squeaking - sometimes, I have to treat the tapes in the squeaking area a couple of times. Given the volume discount implicit in the economy size versus the regular size, a discount of at least 25% seems reasonable for the Last Formula 10. I believe that the dealer cost is around 60 points (40%). AFAIK, Last is a pretty small operation. Walt Davies, who started LAST is still the principle person there. I don't think they sell enough of either Formula 9 or 10 to be in stock in hifi dealers.