What Maverick said. Office, vids, some and net surfing can be very well done with a cheap laptop. Of course unless Office means enormous Excel sheets with extremely complex calculations. Which reminds me of this student whose chemistry formula calculations could take three days each on his dual CPU computer back in the nineties...
Most of my customers are people who'd like a reasonably priced or even a cheap laptop for the tasks you mentioned. My advice: After you've set your budget, look for the mechanics. How sturdy the hinges are? How stiff is the lid = if you close it from one corner, does the other one follow? Don't buy one with a twisting screen! How does the keyboard feel with your typing style? Does the wrist rest give in? Last but not least, what's the image quality in different light conditions? Don't forget viewing angles especially on a larger screen!
RAM is the most influential thing concerning speed, although the need of it can be masked with an SSD. They make swap file quite fast but IMO that's a workaround instead of a solution. 4 GB will do, 8 is nice especially if you have multiple programs running at the same time. Of course the CPU matters, too, but anything past a Celeron should do very well.
