to tool up how much it is…

…although its should not have changed much since back then )

you can easily look up the address if you wrote it down.

just replace with your address: https://blockchain.info/address/1C3RiLE1M5BsGHH5GDhTwjTmYquawd6aKj

and of course there are many other site that do the job of a "blockexplorer" if you need a term to search for.

prices you will find on market places and exchanges like poloniex or kraken.

to actually use the funds

you'll need a wallet software that can read your private key format and can either create a transaction to be transmitted or send it to the network directly. you will find a list to start with: https://www.weusecoins.com/en/find-the-best-bitcoin-wallet/ and some other places like the bitcoin wiki and other forums will give much more.

To convert private key formats you can use – for actual private keys with an offline copy – tools like e.g.

• bitaddress.org (source)
• iancoleman's BIP39 (source) – this is a good starting point to dive deeper as newer BIPs are implemented that enable you for usage of e.g. SegWit enabled addresses.

I cannot recommend you anything without knowing what is your device/operating system etc.