It depends. If you have a sniper already, I wouldn't get another. However, if you have a perm assault rifle, I'd buy a perm sniper. Actually, if you have a perm assault rifle BESIDES your M16A3, I'd just do a default weapon change and make your M16A3 an SR-25. Or, just wait until hopefully a perm L96 comes out (which SHOULD be coming out in the next month or so I hope). That's what I'd do because snipers are so expensive to rent. Oh, and $20 a month is a lot for a hack...Just saying.
Perm weapons would be good. Getting weapons for 90 days, People usually get bored of it. But varies between people. For me, i would maybe get a gp hazard case? could get lucky. GP would be useful for future preferences. Lt + get good things you can buy with gp.