Ryan, linking to the AP story, presented Ketchum's quote as benefit of the Republican tax overhaul, but then deleted the tweet after online criticism that touting such a small amount made him look out of touch.
Former George W. Bush ethics lawyer, Richard W. Painter said that Ryan "should be ashamed of himself" for publishing the tweet.
Mr Ryan posted other links this week to media reports of how people are seeing more meaningful increases in their pay - some said to be as much as $1,000 (£708).
Costco is a American budget wholesaler of home furniture and appliances, with an annual membership costing $60 per year.
Ryan's tweet was the latest show of Republicans patting themselves on the back for the tax bill, which slashed corporate taxes.
Just when you think Paul Ryan couldn't get any more delusional, he goes and does exactly just that.
Another tweet that spread like wildfire was one by California Lt Gov Gavin Newsom who tweeted a screenshot of Ryan's tweet and wrote, "Guess someone told Paul Ryan you shouldn't go around praising yourself for giving a working person an extra $1.50 a week - because he deleted this tweet".
House of Representatives Democratic leader Nancy Pelosi also criticized Ryan's tweet.
Ryan's opponent in the 2018 congressional elections, Randy Bryce, also responded to the tweet, taking the opportunity to try to juice his own fundraising efforts. Ryan's tweet celebrating a public high school employee earning an extra $1.50 per week went mega-viral-and not in a good way, with countless people mocking and deriding the Wisconsin congressman for the tone-deaf tweet.
After the tax bill passed, billionaire industrialist Charles Koch gave Ryan nearly $500,000 in campaign contributions.
The $1.5 trillion tax cut, signed by President Trump in December, includes a permanent 40% tax cut for corporations, a change Republicans say is long overdue and desperately needed to make America more competitive in the global economy.