Tech 1 BPO's are purchased from NPC Vendors
Tech 2 BPO's occasionally surface for sale (your immortal soul will generally not cover thier cost)

Tech 1 BPC's are researched at Stations or POS's from a BPO
Tech 2 BPC's are made through invention (or by copying a BPO)

Had a t2 frigate BPO offered to a corp I was a director of once. We decided not to buy it as it would have taken about 20 billion to purchase and about 2 years to make up the investment through nonstop production.

From what I understand only a set amount of each exist at any one time. And one has to be destroyed before a replacement spawns for one very lucky person.

The BPO lottery system actually very slightly pre-dates my time, so I don't know off the top of my head how it worked exactly, but I can say that it no longer exists.

T2 BPO's are unique and irreplacable items. You will often find that buying one to manufacture on the open market is not practical due to the huge upfront cost you must recover. However, as collectors items or alliance assets to ensure supply, they are still available, if you can find a seller.

Modern T2 production is performed via the invention system, which creates BPC's instead.

These guys should of took the time to explain T2 BPOs....

Eve had a lottery system at one time. We'd use R&D agents, to get points for lotto's. If we won we got the T2 BPO. A few things happened, one of which was the Band of Brothers Alliance (BOB) rigging of the lotto system. They had a CCP employee in their alliance that gave BOB an unfair advantage at winning some of the lotto's. Much drama was started, anyhow CCP finally did away with the system. Those that have T2 BPOs were able to keep them. There are few out there, and they are extremely valuable. One of the most sought after T2 BPOs would be the Hulk. It's value so extreme that it would take a couple users of none stop production to repay the cost you'd spend on it. CCPs new system for handling T2 production is the invention system. I'm sure you know of this system, but if you do not. You take a T1 BPO, copy it into a BPC, and through a process in which the BPC is destroyed and possible other items as well. You can (there is chance for failure) make a T2 BPC. The specs on it change base on several factors, but usually most have negative ME (material efficiency) and PE (production efficiency) values resulting in higher mineral/material requirements and longer build times. These BPCs can not be researched to make them more efficient. This is why the T2 BPOs hold such a high value, they can be researched to be very efficient. This often leads to the argument that T2 BPOs for T2 prices to be to low for most members to compete on the market. This actually isn't true, as the T2 BPO inventories can not keep up with any where near the actual EVE market demand for T2 items. Instead invention still control the price of items, while those with T2 BPOs simply take in higher profits then those without. CCP has so far refused to remove T2 BPOs, and there is nothing suggesting they will. CCP also has made it clear they will not add new T2 BPOs to the market, and given how the T3 BPCs are produced, it would be fair to suggest CCP may very well never produce a BPO beyond the T1 variants.

I hope this helps explain a little more then the previous answers.

PS: T2 rig BPCs can be found in some sites you scan out. They will have a 0ME/0PE and 2 runs.

I wish I would have been able to give him the history of the T2 BPO, but I'm not that old

Had a t2 frigate BPO offered to a corp I was a director of once. We decided not to buy it as it would have taken about 20 billion to purchase and about 2 years to make up the investment through nonstop production.

Had a t2 frigate BPO offered to a corp I was a director of once. We decided not to buy it as it would have taken about 20 billion to purchase and about 2 years to make up the investment through nonstop production.

From what I understand only a set amount of each exist at any one time. And one has to be destroyed before a replacement spawns for one very lucky person.