I am posting this hoping to help somebody else out, surely there are some other beta-engined Hyundai owners on here.
I have a 2010 Elantra Touring, which takes the Hyundai filter 26300-35503 (apparently this is their most common filter, so if you have a ~1995-2012 Hyundai you probably use this filter). Since I bought this car I have been buying oil filters from Hyundai dealers (to make them happy regarding my warranty) and paying ~$15-$16 per filter each time. Obviously this is a huge ripoff but I didn't think that I had any other options so I just bent over and took it for the first 5 oil changes. I tried different dealerships but due to a lack of planning on my part I was always in a hurry to get a filter now and just paid what they asked
After reading on another forum that Hyundai and Kia share a lot of parts between their brands (sometimes entire cars...), and that parts are often cheaper from Kia dealers despite being identical parts in identical cities I got curious if this applied here as well. Taking that part number I called a few Calgary Kia dealers and found their highest price was still nearly $5 (~35%) cheaper than the cheapest Hyundai dealer.
At all dealerships I asked for 1x 21513-23001 crush washer (gasket) and 1x 26300-35503 oil filter.
All charges are without eco fee and GST:
Crowfoot Hyundai - $15.13
Calgary Hyundai: $14.11
Precision Hyundai: $14-ish (his computer was broken but he said it was just over $14 pre-tax)
Kia city: $8.98
Northland kia: $9.33
Eastside Kia: $8.25
Based on the above (and the fact that they were open on Saturday) I went over to Eastside Kia and managed to talk my way into a discount if I bought more than 1 filter at a time, and when buying 5 I got them down a bit more to into the $6.XX range per filter and crush washer. This is cheaper than I can get them for online!
Compare this to Hyundai, where every single Hyundai dealership refused to reduce the price at all no matter what I tried - buying more than one at a time, asking them to match online retailers, asking nicely for wholesale pricing, buying other parts at the same time, nothing.
TL;DR: If you own a Hyundai that takes a 26300-35503 oil filter you are getting ripped off at every Calgary Hyundai dealership, buy them from Eastside Kia.