Sloppy Seconds Condoms. I can see the ad campaign now (actually I can’t). 
Your friend is going to learn the hard way.
If he honestly can’t afford to buy more condoms, then he needs to get more creative in his sex life. There are lots of things to do that don’t involve ejaculating into anybody’s orifices and still feel pretty damned good.
Why is his sex partner agreeing to this? Or does she know?
Tell your friend to compare the cost of a new condom with the cost of raising a child from conception through college.