You could possibly put some spermicide at the end of a condom. I could be wrong, but I think the lube on most condoms is some kind of spermicide, so don't take my random internet guy word for it.

Additionally, when you bust a nut, you can pull out as well so that you are not risking busting through a condom tear or a hole in it. The likelihood of pregnancy drops even more drastically because the probability of two methods, pullout (60% effective) multiplied by condoms (98% effective) is combined statistically.

You already ruled out the other two options you have, so that is all you can do really on your end. Your other options are filtering out for girls who also happen to be taking birth control or have an IUD etc. So take that earlier calculation (60%) by (98%) and multiply again by another 95%+ and you have virtually impossible odds of knocking up a girl, on top of the already low odds from condom + pullout combined

Have enough money for the morning after pill.