Retail stores designate .88 for clearance pricing.
Most stores have .99 = regular prices items, .98 special promo pricing, .97 = means something else. This is how they keep track of their sales.
Look at all the clearance stores, i.e. Brandsmart, everything ends in .88
Same reason why prices end in $1,999. Makes one think they are spending less compared to a purchased priced at $2,000. There are quite a few web sites out there that have reports on pricing statistics and research they have done.