Many of us use Panasonic LinearPlus tapes (the lowest-priced tapes) in our Sonys.
I have shot HUNDREDS of these without ANY problems at all in my PD150 and GV-D900 deck.
I also use them in my Canon GL-1.
I always go to eBay to buy them, in-quantity, for under $3.00 per tape.
The more you buy at once, the less the postage will be per tape.
You are more than welcome to choose Sony brand as well, I just can't find them as easily for the same low price.
Search for "Panasonic DV tape" or "Sony DV tape" and check the seller's Feedback rating.
As I say, I have bought and used hundreds of tapes this way.
I get these tapes in all the original sealed packaging, brand new, no problems.
Just as examples (I 'm not recommending any seller in particular, its up to you.)
Panasonic-
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=14962&item=309261501...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=15073&item=381100377...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=20332&item=381048977...
Sony-
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=15073&item=381066938...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=15073&item=381088598...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=21163&item=381106446...
