It can get annoying typing out the full name of an item in the 'Buy' tab, especially when the names are all case-senstitive and can be quite long. Here are two quick tips to speed up the process.
a) If you have an item in your inventory and want to do a quick 'Buy' search to see how much it is selling for, simply ALT + Left Click the item in your inventory and the search bar will be auto-filled with the complete item name.
b) If you don't happen to have an item in your inventory but know its name, you can simply enter the first letter of each word (capitalized) in the search box. For example, you can search 'T S L J' instead of Thin Soft Leather Jerkin. Some item names share the same initials, so you can narrow the search by adding a second letter in lower-case. For example, 'M W F' will result in Major Weapon Flux and Minor Weapon Flux. If you only want Major Weapon Flux, search for 'Ma W F.'