2fer or 3fer or 4fer describes a technique for brokering technology. Look for or own a monopoly tech. Buy it if you need to, then trade it around for technology you don't have. The most important step is to go back to all the trading partners and see what they will offer for what you have just acquired. So you get 2 technologies by investing in 1, hence 2fer, or three, hence 3fer.
The technique works best when you are the contact manager. In other words you know all the nations and the other guys only know one or two. That's why early exploration is so important either by land (you don't know Alphabet so can't build curraghs or aren't on a coast line) or by sea.
Knowing how much a tech costs in beakers is marginally useful knowledge but not critical and you can calculate that by setting your research rate at faster than 50 turns and multiplying turns by the change in gpt.
Finding out how the AI values tech is simply a matter of offering it and see how they bid, then making the best deals possible.
The cardinal error in trading is to buy just to have. Only make an offer when you have another prospect waiting. I will frequently delay any early trading until I have at least one additional party for any trade I might make. And I usually never make a deal with the first people I meet. If, for example, everybody else on the map starts with Pottery and I don't and I'm pretty confident I will make one or more new friends quickly then I will wait to make any deal for it as it will only get cheaper with each new contact.
The technique works best when you are the contact manager. In other words you know all the nations and the other guys only know one or two. That's why early exploration is so important either by land (you don't know Alphabet so can't build curraghs or aren't on a coast line) or by sea.
Knowing how much a tech costs in beakers is marginally useful knowledge but not critical and you can calculate that by setting your research rate at faster than 50 turns and multiplying turns by the change in gpt.
Finding out how the AI values tech is simply a matter of offering it and see how they bid, then making the best deals possible.
The cardinal error in trading is to buy just to have. Only make an offer when you have another prospect waiting. I will frequently delay any early trading until I have at least one additional party for any trade I might make. And I usually never make a deal with the first people I meet. If, for example, everybody else on the map starts with Pottery and I don't and I'm pretty confident I will make one or more new friends quickly then I will wait to make any deal for it as it will only get cheaper with each new contact.