On a budget? I just put drops on this hybrid, and used Tourney trigger shifters ($15 on line). Total cost was very little, way under the cost of those shifters you are looking at on Amazon. The more resourceful you are, the lower the cost. Think co-op, friend's parts bin, donor bike, or whatever.

Trekking bars are another thrifty option for a hybrid conversion.

[IMG]1992 Schwinn Crosscut 16 inch by Bills Vintage Steel Bikes and Parts, on Flickr[/IMG]

Started with this, pulled out of a scrap pile:

[IMG]1992 Schwinn Crosscut by Bills Vintage Steel Bikes and Parts, on Flickr[/IMG]