I don't own every console out there so I may have missed previous cases of this but is the PS Vita the first console to have no standard price for full length games? The home consoles have an unofficial price standard of $60($50 for Wii) that all full length games release at whether it's at retail or the digital price. Almost every full length game was released at that standard price and then depending how good it was selling it would see price cuts over time in increments of $10 usually $60, $50, $40, $30 and Finally $20 and sometimes $15. However looking at the PS Vita games, there seems to be no standard price. I thought $40 was the standard price then down to $30 and $20 but I started to look at how much the big AAA titles for PS Vita were selling for on PSN. Assasin's Creed: Liberation and LBP Vita were selling for $36 on the PSN, Uncharted is selling for $45, Madden and Silent Hill are selling for $40, Shinobido 2 and Dynasty Warriors Next are selling for $35, Hot Shots Golf: Open Tee 2 and Smart As.. selling for $30, Little Deviants and Modnation Racer are selling for $27, Ridge Racer Vita and Touch my Katamari are selling for $25 and when COD: Declassified comes out it will be selling for $50. PSN has full length PS Vita games selling at $50, $45, $40, $36, $35, $30, $27, $25, $23, $20, $17, $16, $15, $13, $12, $11, $10 $10.50, and $8. Why do you think there is such a variation of pricing for Vita games? Why have the home consoles not followed suit? Will we see COD or GTA games selling at a premium $70 like we do with COD: Declassified and Uncharted on the Vita? Will there start to be console games that sell for $52 or $47 instead of the standard $50 and $40 prices? Or is it temporary and  the video game publishers are still just trying to figure out the best price points for the Vita userbase before it develops a standard price pattern? 

Please can you use Paragraphs, thats quite a big chunk of text.

To answer the OP, The variation of pricing is actually due to the dates most of them titles were released.
But yes Madden/Fifa/Uncharted/Call of duty/Liberation all $50 kind of makes sense. Most other games $40. They just know that people won't buy the other games at $50, so why bother putting them at that price for it too fall so quickly?

It's this way because SONY wills it. Publisher chooses the price for the game at both retail and PSN. At launch, SONY themselves had Uncharted:GA for 50$ sitting next to LittleDeviants for 20$ at retail and said that PSV will have an open pricing scheme from free to 50$. They had 4 games that were free at launch. 3 AR games and Motorstorm RC. The general retail price seems to be 40$ though.