Is this legal. "Firm Fixed Price bulk funded estimated quantities purchase order". The idea being the contract would be for ordering an unknown quantity and paying for only items ordered.

Sure, perhaps an IDIQ would be a better choice contract type. That aside, anything out there that suggests this can't be done?

What is the consideration that makes this a contract?

volunteer donated blood (think blood drive) and money.

I guess a follow up question i would have is, would it matter what the consideration is? What if i had a trend that shows my car breaks down every 4 months, so i want a preventative maintenance contract in place for someone to fix it in the event it does break down. it is estimated that it will break down 3 times a year, so a bulk funded contract is established for an estimated three repairs. If it breaks twice, am i still liable for that third service regardless if I needed it or not?

Why are you asking about bulk funding? Bulk funding is not what you described in your first post. The FAR describes "bulk funding" as follows at 13.101( b )(4):

Bulk funding is a system whereby the contracting officer receives authorization from a fiscal and accounting officer to obligate funds on purchase documents against a specified lump sum of funds reserved for the purpose for a specified period of time rather than obtaining individual obligational authority on each purchase document. Bulk funding is particularly appropriate if numerous purchases using the same type of funds are to be made during a given period.

That's not what you seem to be asking about. Bulk funding is not about issuing "estimated quantities" purchase orders.

Can you issue an "estimated quantities" purchase order? Why bother? Issue a blanket purchase agreement and place BPA calls for repairs when you need them.

The requirement was for blood for a hospital. This particular hospital averaged 300 orders each year over the past 5 years. To me, it doesn't seem feasible to issue a BPA call each time an order is needed. sometimes this blood is needed within a couple hours.

The problem is, you cant really forecast when someone is going to show up at an ER, so the idea was, take a lump sum of funding, put it on a PO, and pick up the phone or sent an email to order as needed.

*the analogy to the repairs was just to ask why would consideration matter?

You know, a BPA call does not have to be a document issued by an automated contract-writing system. A BPA call can be just that, a telephone call by someone who is on the list to make calls. And the BPA can specify that the Government will make a payment at tne end of each month for that month's calls.

Understand about the BPA and calls being made by specified individuals.

I did loose this argument at work and ended up going with an IDIQ. Their reason was you couldn't use a FFP PO to order an estimated quantities. No one proved to me you cant, so my argument was, why not?

A purchase order that does not stipulate a specific quantity for a specific amount of money cannot, by definition, be firm-fixed-price. Are you telling us that you do not understand that? Really?

Assuming that you have told us the complete story, whomever it was that you lost that argument about a BPA with doesn't know much about contracting. A BPA would be the perfect instrument for the requirement that you described. But since you lost the argument and none of us can win it for you, you're on your own. You have the great misfortune of working for an ignorant organization.

Good luck.