The unit powers when plugged in. Once unplugged, the unit shuts off. When first turned on, there will be blank lines on the screen. Once the unit warms up, the lines disappear. THE ANSWER IS "YES, WE DO COMBINE SHIPPING!" THE MORE YOU BUY THE MORE YOU WILL SAVE. PLEASE CHECK OUT THE REST OF OUR STORE AND ADD TO YOUR ORDER. WE WILL SEND A COMBINED INVOICE ONCE YOU LET US KNOW YOU ARE DONE SHOPPING. If there are any questions, please message us. What you see is what you get! The picture you see is actually what you are bidding on. No bait and switch here. We treat people the way we would like to be treated. We love what we do and know what we are doing. Our feedback is awesome, so rest assured you will get what you pay for and fast. We ship out the day of or the next day after we receive payment.