Remember there is always the option of waiting it out on stubhub with the hope of prices dropping as the date gets closer, especially if you are fortunate enough to have two shows back to back where you live.
For instance when Macklemore came to NY he played 3 shows at MSG, and tickets were expensive. I was curious and checked stubhub the day before the first show and GA was $80. Granted I don't think Katy will come that low but my guess is it will eventually drop around 150-200 depending on your venue.
I shelled out the ridiculous amount of cash for RS VIP because I was stressed out and stuff but for my friends we're gonna wait and see probably all the way up to the week of the concert. Keep in mind, most people who go to stubhub are not the dedicated fans who want to stand the whole show, they are more looking for a lax time. That being said, there are more RS tickets being added each day (at least for Barclays) and no one buying them. Prices will plummet.