Data Capture

We need to capture Asset Data into excel on the move . We have an idea that a tablet PC is an option but an expensive one. Do Smart Phones or another like but more affordable device meet the bill. In actual fact we are willing to look at any option and give it our best endeavour to solve this problem. We tried Laptop but the duration in the field is 7-8 hours and the battery gave up about halfway. The weight was a problem and no stylus meant keyboard activity which is cumbersome. The problem is cost (as always) and practicality.