The questioner appears to be asking how he can compare the cost to renew his domain with the cost to transfer it at different registrars, since his domain will appear as "unavailable" if attempted to be searched on or registered.
With his current registrar, the renewal price will most likely be higher than he initially registered it for, especially if he used a discount or introductory offer. He can simply add the domain to renew to his registrar's shopping cart without paying for it in order to see the renewal cost. Often there are discount or "promo" codes available for different registrars if searched for in Google which will lower the renewal cost somewhat.
Even with a discount, renewal fees for registrars are almost always higher than their introductory registration fees - that's how they build business. Some will provide a 1 year introductory offer or discount for transferring a domain too, but the subsequent years will be at their renewal rate, which can usually be found on their websites, typically in smaller print like a footnote.
In order to confirm the price or discount to transfer a domain, you have to first unlock the domain with your current registrar (be sure to lock it after you're done). Then the domain will say "available" to transfer instead of unavailable.
Tip: It's a good idea to turn off "autorenew" for the domain(s) if you plan on shopping discounted transfer rates. However, be extra careful not to let the domain expire or you may end paying an exorbitant "redemption" fee, or even losing the domain.