The dose depends on the weight of the horse so I will give you my horse as an example.
Horse weight is 650kg, dose is 1ml per 50kg so daily dose is 13ml.
I bought 1litre of Regumate from my vet for about £110 and at that dose it will last 77 days ie £1.43 per day.
You can buy it in a 150ml bottle for about £32 which would last me just over 11 days ie £2.78 per day. I suspect this is the size of bottle you are talking about. My vet tried this size first to see if it worked on my mare.