Yes, I got mine from Rittenhouse. $30 is not unusual for a Rittenhouse Rewards card for a Marvel (or other relatively popular) set. Some of the rewards cards are cheaper but that's a reasonably typical price. However, it's also no cheaper to do with points. By the time you've shipped the empty packets, paid for registered shipping to a US person and then paid for them to ship it (not registered) to Australia, eBay is no more expensive.
I gave up on sketch completism almost as soon as the sketches became artist choice. Some of the earlier sets (eg Stargate Season 5) have each artist doing multiples of the same sketch and that was just another chase card. I'm very glad I haven't really tried to do sketch completism as the number of artists in each set just keeps growing. What I do instead is try to avoid having multiple sketches from the same artist and I also try and spread the characters around. Other collectors do the exact opposite - they collect a particular artist or a particular character.