Which powerbank or portable chargers are good and hold a lot of charge? I need one for work as I use a tablet all day for work and I am not in an office.
My question is:
Which is a good one and works on samsung tabs as I know most dont
What price range am I expecting to pay for one?
Anker is a well known brand, though it can be pricey.
Yoobao is also another brand, but beware of some fakes on ebay.
Another solution is go DIY. Source your own 18650 lithium cells and buy a portable USB enclosure for it. The capacity will depend on what cells you buy.
Try Fasttech for some power banks. http://www.fasttech.com/