Harbor Freight Tools offers the Pittsburgh Drive Wobble Socket Extension 9-Piece Set, model no. 67971, for $14.99. Coupon code "63365768" drops it to $10.99. Opt for in-store pickup to avoid the $6.99 shipping fee. That's the lowest price we could find for it shipped by $15. It features 1/4", 3/8", and 1/2" drive wobble socket extensions.
There's a less expensive way, and then there's the way that works for you. The two may not be the same.