It was something my ISR had me sign. 5k upon entering and 2.5k at 1st and 2nd anniversary, for 11 and 12 career fields only. This obligates you to a three year commit. He said they may change it before I enter the reserves officially in May, but I should be grandfathered in. Also, I signed up for the 3:1 PC, but since I did it in Dec 13 (FY14), and there's now a 1:1 pgm, I'll qualify for the 1:1. You may need to ask about this bonus, since he said not everyone knows about it, especially different units.
One more thing. I'm scheduled to pin on Maj in April and leave in May. When ISR put me in the scroll in December (you need to press your ISR to do this as transferring to the reserves w/o a break in svc depends on it and normal process takes about 4 mos--don't need to be pc approved to do this, do it as soon as u submit ur app) they entered me as a Capt. This is a prob cuz if u get entered as a Capt, you'll be a Capt to start, even if the position authorizes a Major, according to ISR. BL, if ur expecting to make rank make sure to tell ur ISR, as there are a certain number of rank slots per time period and it may affect ur transition; can be a pain to change.