When I went to the Kake Soba Shop twenty years ago, it was only 200 yen per bowl!
As a stock phrase, this will suffice. However, if you are actually at the shop itself, the phrase can be shortened to, 'Twenty years ago, this was only 200 yen!'
A bowl of kake soba at that standing-only soba restaurant cost 200 yen when I went there 20 years ago.
I paid 200 yen for a bowl of kake soba when I went to that standing-only soba shop 20 years ago.
A bowl of kake soba used to cost 200 yen at that standing-room-only soba shop when I went there 20 years ago.
「立ち食いそば」は standing-only soba restaurant や standing soba shop、「かけそば」は buckwheat noodles in hot broth のように説明できますよ。
英訳① cost ...で「…（値段）がかかる」。
when I went there 20 years ago で「20年前に行ったときは」という意味になります。
英訳② pay ... for ～「～に…（値段）を払う」。
英訳③ used to ...で「かつては…だった」。
アメリカ合衆国 
