Amazon offers its Prime members the Ronco Pocket Fisherman, model no. PF100100GENB, for $15 with free shipping. (Non-Prime member can spend $35 or more to qualify for free shipping; otherwise, shipping adds $5.58.) That's the lowest total price we could find by $5, although we saw it for a buck less with pickup last summer. It measures 9" long and includes a hook, bobber, weight, and fishing line.

Update: Walmart now offers it for the same price via free Site-to-Store pickup.