I have a number of pajama bottoms my DW bought me from Old Navy a number of years ago. Although I don't wear them to bed, if it's cool out then I do wear them around the house...as a matter of fact, they are my "life of leisure" uniform (with a t-shirt...I don't want to bother the neighbors THAT much when checking the mail!). I have had them more than 5 years and besides a little fraying at the bottom of the leg cuffs, they are good as new and since they came from Old Navy, I assume they cost no more than about $10 each.
On the subject of FIRE, or ER, or FILL IN THE BLANK WITH A CATCHY RETIREMENT TERM blogs...yes, there are way, WAY too many of them.
Old Navy has really great soft tank tops too. They are my usual lounging outfit.