Big box retailer Best Buy has slashed up to $150 off the U.S. price tag for Research In Motion's PlayBook tablet computer for the Labor Day weekend.

The 7-inch PlayBook launched in April to scathing reviews that it was not ready, as it can only connect to RIM's servers for corporate systems such as email via a BlackBerry smartphone.

The 64 GB and 32 GB versions, which usually sell for $700 and $600, respectively, were both advertised at $549.99 on Best Buy's website on Thursday. The retailer was offering the 16 GB version for $449.99, a $50 discount. All the deals end on Monday.

It is not uncommon for retailers to discount smartphones and other electronic devices during the busy back-to-school shopping period.

Apple's iPad still dominates the tablet computer market.

RIM said in June it had shipped 500,000 PlayBooks.

Apple has sold close to 30 million iPads, whose prices start at about $500. Apple launched the iPad early last year, and spawned a string of copycat devices.

Current versions of the PlayBook cannot connect to cellular networks, giving carriers little incentive to promote them. RIM is expected to launch cellular-enabled PlayBooks soon.

Hewlett-Packard has killed off its TouchPad tablet, but will produce one last run after a sales frenzy caused by its price cut for the device to $99 from $399 and $499.

(Reporting by Alastair Sharp; Editing by Janet Guttsman, Phil Berlowitz)