Best analog high pass filter for low $

Likely I will go high level connection from amp to sub and just let the sub bass fill in where the mains can't quite hit (15-40Hz or so)
But, doing all sorts of research and thinking about different ways of connecting got me thinking about how IF I did decide to go with RCA and offloading some of the bass that the Mains CAN hit to the SUB, then what would be the best way to do this without going digital (NO ADA conversion please!). I assume this can be done with a high pass filter, but which one is a good all analog x-over that could do a good job without degrading the SQ substantially? I saw the Outlaw Audio ICMB, but it looks like that has been discontinued. Are there any other good options under $300 that I should know about similar to the old Outlaw unit?

BTW...Another option is Vandy 2wqs - they have their own connection system that is pretty freakin' cool and I have definitely not ruled out that option either. Just trying to figure out ALL my options.

Thanks,