www.rockymountainatv.com has the tusk e-brake block off for around 8 bucks + shipping. It comes with the o ring also which most over brands don't. Shipping is a little on the high side so if you need other parts like oil filter, fuel filter, gas cap, or whatever you may want need shipping is way cheaper.
I was going to buy just the e-brake block off from them and they wanted $7.17 to ship it. So I bought all the above, tuck gas cap with breather, K&N oil filter, 2 fuel filters, and shipping went up to like $7.47.