A Sony VAIO laptop would not be affordable in most cases for students on a tight budget. This line of laptops ranges from $500 to over $1600, out of the price range of someone who is on a tight budget.
While Sony Vaio Laptops are a good product, they do not rank significantly higher in quality than other name brand laptops. Sony Vaio Laptops do usually carry a higher price tag than conformable offering from competitors.
Sony's website has information on their laptops. You can also find information on Sony laptops from places that sell them. You can also find reviews on them. It also is a good idea to try your laptop out in the store before leaving.
This is very subjective as people have different definitions of good. Lenovo's ThinkPad laptops have a very good business reputation with specialist business apps. Apple, Dell, HP and Sony are also considered to be good business laptops.
Sony laptops are sold in most good electronics retailers, as well as being available from the Sony Online Store. For a more competitve price it is advisable to look for deals which are widely available both online (on Amazon), and in the high street.