J or j can be used - both are acceptable.
This replacement of 'J' and '£' arises from the personal messaging system. It inexplicably replaces '£' with 'J' before sending, presumably because it cannot store or send '£' as it is not a letter, and as UG is American, the £ is unlikely to be used.
- cheapest I've seen is J500!
-T.I. - 24's:
By tha niggas getting head from a J, loose your leg when I spray and your dead from decay, stay ready for the raid pay heavy for the yay I told my class kiss my ass i make 11 everyday
-JR Get Money - Trap All Day:
Im in the trap all day, cell phone ringing off the hook from the J's, the blow sitting mad counting money in the shade, there sure aint no other way id rather get paid.