Although price might be the first consideration; functionality, your working environment 
and device durability should also be evaluated.
The majority of our customers purchase the ‘mobile computer’ style of scanner rather than a tethered, presentation or fixed device and in this discussion I will focus on this range.
Functionality: this should be a key consideration and geared around your specific business. Do you know the type of barcodes you use or will need to use? How much information do they need to reference as this will affect whether you choose a 1d or 2D scanner? Do you need a long range capable scanner? Will your warehouse team be 'up close and person' to your products when scanning or will be the item be on the top racking shelf? What size will your barcode and dispatch labels need to be? How much space is there on the product packaging or racking area? Do you work with refrigerated products? Does your warehouse run 24-7?