Is there any? Esp. in JB and KL? Botox is sold by cost per unit.. so its best to inquire about that... Some botox is very cheap because its diluted.. but can tell that the effect isn't there..
Alternatively, from observation if you can tell that the $500 botox works as good as the $1000 botox then obviously the $500 botox is same units as the $1000 botox... e.g. usually 60 unit each side.