Different airlines do it different ways.
Some will give a type rating and bond you, some pay for your type rating and expect you to pay it back over a period of time. I have occasionaly heard of people getting a type rating with no strings but I haven't heard of an airline that expects you to pay for a type rating up front although I stand to be corrected.
If you are concidering paying for a type rating be very cautious. A type rating alone is somewhat devalued without the hours on type to go with it. There are people out there that have paid circa 18 grand in the hope of improving their prospects in these desperate times and have nothing but a bit of paper and a hole in their pocket to show for it. I can think of one person in particular who was told by a certain LCA that they would give him a job if he got himself a type rating, not supprisingly they went back on their word.
Then of course there is 'sodslaw' to take into account. You could go off and get yourself an a320 type rating only to find everyone is screaming out for 737 typed pilots.