An Instep bike trailer is a discount option.  They are not as sturdy as the premium brands like Burley, or Chariot, but they certainly get the job done. 

Most have conversion kits for changing the carrier into a stroller.  Many also feature 'no-tool assembly' so that switching is quick, and hassle free.

Make sure to check out the VIDEO below for a general introduction to bike trailers.

	Wheels	Frame	Canopy	Conversion Kit	Other
InSTEP Rocket Aluminum bike trailer	-aluminum -spoked rims	-aluminum	-weather shield	Yes	-Rear storage -Safety flag -internal pouches -no tool conversion
Instep Quick N Lite	-aluminum -spoked rims	-aluminum	-weather shield	Yes	-weighs 25 lbs -no tool assembly
Instep Quick N EZ	-plastic -mag rims	-steel	-weather shield	No	-no tool assembly