I've been doing MTI's Ruck Based Selection program for a couple month's now and it's a very solid training regimen. I will say that going into their programs with a good level of fitness is recommended because they're not easy if you're pushing yourself and some times it feels like there isn't enough time to fully recover in the beginning. I purchased the athlete subscription which is $35/month and for me that is a good price for what you get and have access to.