Free software options... HKN, AutoHotKey, Octopus, Mojo (which is in development, not a finished product).

Keyclone is a solid option, as far as key replication goes, but a little lacking on mouse broadcasting which can be nice at time. This is $20 for a lifetime license.

GameCommanderPro, is a pay option. Not sure if its one-time or a subscription.

IS Boxer, is a subscription option $36/year or $10 per quarter.

They all offer a trial period, so you can decide if the program is for you.
$20 once, or $36/year isn't much... compared to the monthly subscription of the game...
Not knocking the free options, but you also pay for what you get.