Getting replacement parts, especially batteries, can be a rather expensive adventure if you are relying on original manufacturer parts. Like toner or ink, the original manufacturer batteries are often really costly, but there are clever alternatives as well. There are manufacturers specialized in building replacement parts with the same specifications as the original ones but at a much lower price.
Many manufacturers claim third-party parts or batteries wouldn’t offer the same stability or performance as the original ones, but these claims are often only made to ensure that people buy overpriced original parts. Many reviews and long-term usage studies of leading electronics magazines show that todays third-party batteries are comparable to original parts in quality, lifetime and performance.
If you are buying a battery from a third-party manufacturer, you can simply enter the original part serial number of name on a website like Laptops for Less and then lookup the corresponding third-party model. Especially Laptops for Less offers a great quality at very low prices. Having a replacement battery is always handy, especially if you are travelling a lot. Charging can take hours and while you are away from home you may not always find a place to recharge your original batteries, so having a set of pre-charged replacement batteries is a measure to avoid embarrassing situations, like e.g. your laptop shutting down in the middle of an important business presentation, while watching a good movies or being in the middle of a world of warcraft raid or similar.