Research. Before going somewhere else, you have to research first. Find out more about an air knife, what its functions are, where you can possibly buy it, and the estimated price.
Check out the stores that sell it. If you can find a store near your locality that sells one, go ahead and check it out. However, just before you put efforts in driving to the nearest store, why not check out some online sites that sell the item too?
There are a lot of sites that offer air knife. You have to first check them and compare prices. If there are sites that are quite dubious, drop them. When you have already narrowed down your choice, try to pause and make your decision.
Once you have already made a decision, or if you have not yet reached it, you can try to inquire further on that site. There are numbers in their website for you to contact. Once contacted, you can clarify some issues regarding the price, manner of delivery, warranty and many more.
If you have already chosen a brand, a site, and you are confident of it, you can go ahead and close the deal. Make sure that you receive the electronic receipt as you pay online, via credit card or an online money site.
Upon receipt of the item, check it out first. If you have no problem, you can sign the delivery paper. If you have problems, you better ask the delivery service company as they might cause it. By then, you can contact the site where you bought it to clear things out.
Keep the important documents so that if any problem will arise soon, you already know what to do.
Now that you know these basic steps in buying an air knife, you can go ahead and make your move!