actually that depends.. if you can rank decently on games.. it may cost cheaper.. but to those who suck and get low on the totem pole... doesn't really seem great..
30 hour weapons cost 6.8k to rent.
If you were using a perm you would repair 1.8k worth during this time.
30 hour weapons pretty much cost 5k then, right.
Average Perm weapons used to cost 27k to 40k.
That means you could rent a weapon 5 to 8 times before you payed as much to perm it.
Thats 150 to 240 hours, 300 to 480 full length games.
If you really like the weapon this much, you could of probably gotten a +5 from fumbi by this time.
This is a long time, it would take a VERY long time to outpay it as opposed to perming it.
If you use more then 3 weapons and switch around, it takes even longer.
Also, the new rentable weapons are +1.
Credited to Xbelnaost of MyS4league
Anyways, thats the evidence that its cheaper :x