and if this is random exchange gift then maybe portable coffee maker will be good,with your budget i think that is enough for cheapest price.i t is unisex so appropriate for men and women.
I think that the tradition for Secret Santa is to have an idea of whom the gift is going to go.
However, some coworkers had a smart idea to make it random for more fun!
Powerback is also good but most of us now already has one,and it is normal for every individual now to have a powerbank so i think try to figure out which is will be more appreciating that those 2.
but of course this is only my opinion guys,no personal attached