For the last few years, we've seen a slow, but steady decline in DVD burner prices. According to DigiTimes, the retail price of 18x and 20x DVD burners is actually on the rise due to tight supplies and increased demands by the US and European markets.
The supply of half-height 18x and 20x DVD burners in Taiwan has been tight since the beginning of May due to increasing demand for such burners in the US and European markets, according to sources in the retail channel in Taiwan, who noted that retail prices rose by NT$30-50 (US$0.91-1.52), or 3%, in May and by NT$20-30, or 2%, in June.

Because of the tight supply, the time from order placement to delivery took 7-10 more working days in May while the additional time decreased to seven working days in June as the tight supply has somewhat eased, the sources indicated. Since the beginning of May, the general inventory level for H/H 18x and 20x DVD burners in Taiwan has fallen from 2-3 weeks to about one week, the sources pointed out.
While 2-3% isn't much, it can add up over time. If you'd like to read more, head on over to DigiTimes.