As per the subscriber agreement, after your contract ends, you will need to return some of the equipment, or you will be charged for it. Dispute resolution with HughesNet is through arbitration.
Does it cost anything after contract is up?
Does what cost anything? Cancelling? No. Continued service? Yes. Your monthly plan fee, the lease charges if you lease and any applicable taxes. An invoice fee? If you've been getting an invoice in the mail the $5 fee for such will continue.
How do I make sure I do not renew for another contract?
You only start a new commitment if you have your service relocated to a new address and you choose the "Zero Re-Install Fee Option", which includes a 12 month commitment, or if you upgrade to a new service type, which at this time isn't possible due to Gen5 being the latest service offering. Upgrading or downgrading your Gen5 plan size doesn't start a new commitment.
Hope this helps.