I think if you want pecans roasted & salted ( like the Waitrose ones??) then you're going to pay extra for the additional work and ingredients involved! If you ask Google there are simple recipes to roast them in the oven with salt and butter which may or may or work out cheaper.
The best price I've found for ready roasted and salted has been £30 a kilo , slightly more for smaller quantities. Ebay has a seller I've used but they're currently out of stock on both their 500g and kilo packs. Google says that
NutsPick sell them in 250g, 500g & kilo packs - the larger ones being progressively cheaper and post free - so £30.00 for the kilo size, (and they appear to do a "subscribe & save" offer with 10% discount for all future orders) so while still pricey compared to plain pecans they're slightly cheaper than Waitrose/Ocado. I'll probably be ordering some shortly as I've nearly run out of my previous Ebay batch.
Robbity