When one is looking for a version of a product that is cheaper than the original or the brand that the product is most known for you can find two different classifications, one the one hand you will have a product of relatively high quality but at a much lower price than normal and on the other hand you will have a version that will be of lower quality and of course still lower in price as well.
Ugg boots are traditionally found from manufacturers in Australia where the Ugg boots originated but now you can find them all over and if you are willing to take the time to do a little research you can find them at lower prices, just know that because they are very popular you will have to invest some time into the exercise of finding the right vendor to buy from due to the fact that there are large numbers of dealers selling the footwear these days.
If you are looking for Ugg boots locally you will probably have a more difficult time unless you look for them in the holiday season when stores are more likely to be holding sales on them. This is true with nearly any item, you will find the best bargains at certain times of the year and during certain seasons. The problem with this is that you may not want to wait the length of time necessary to get a good deal locally.
Of course the simple solution is to use the internet, that's what I do for just about anything and everything. There is virtually nothing that you can't find online and because of the competition you will be able to find great prices as well. In addition to multiple online vendors you can also try some of the various online auction sites like eBay. Just remember when you are bidding to add in the cost of shipping and don't get so carried away with the frenzy of the auction that you overpay. Have a price that you will stop at and don't change it.
If you are merely after the look of Ugg boots and aren't concerned with the quality of authentic Australian sheepskin outers with the warm pure wool inside then you can always buy some cheap knockoffs for next to nothing, just remember the old adage, "you get what you pay for" or in this case what you don't pay for.