Go to tldpros.com and type in a similar version of your domain name. It will show you the renewal fee. Keep in mind it is specific to Enom, but it should give you a good idea.
Another way is to just do a tentative check-out with a similar name and change your number of years to more than one, and your renewal fee will be whatever those other years are.
name.com/pricing is where you can find it. Good registrars will usually have a "price list" of sorts that display registration, renewal and transfer costs per TLD/ccTLD.
So for .coms, I see the renewal fee is $12.99. So whatever domain I buy in whichever auction, that will be the set renewal fee per year? Or is that only with the registrar name.com?
I see that on most popular registrars they have the price list on their websites, it includes the renewal fee for regular domains such as Namecheap or Namesilo