Ok...
So your going to get:
Blackout
Spotlight
Mirror of Mystery Adventure Pack
Earth Element Easter Rabbit Trap
Eggselent Weeruptor
Power punch Pet Vac
And you already have:
High Five
Trail Blazer
S3 Jet Vac
That leaves:
Bat Spin
Cobra Cadabra
Tread Head
Fist Bump
S3 Pop Fizz
S2 Fryno
First off..I don't know about your market. Some options may be fundamentally different where you live.
Basic suggestion:
1.Be Patient and Think Ahead. While it is true sometimes core figures can become hard to find, generally you have them available for a bit. So if you think the Easter stuff is worth the @$9 each, then I would get those first as they may have the shortest shelf life (Personally, I don't need another Earth Trap so the Bunny trap is tempting but I'm thinking of skipping him...or her.) Cobra Cadabra is going to get a variant released so you may prefer that one over the standard. I'm not dying for Power Punch Jet Vac, as I'm going to get the Air mini Pack.
2. Deals...Deals...Deals
I have a general rule not to buy anything unless its under some sort of deal...BOGO40% off or some such type.
(While I have broken it, I have for the most part stuck to it. In general, I would say that we have payed about 25% less than the sticker cost for our entire Trap Team collection.) Do they have a Gamestop "Skylander Day" type sale at EB? Generally every 2 months here...Although I have very little faith in them here, perhaps they are better in your area?
3.Delay what can be delayed. They stage their releases...You stage your purchases.
If you still have a good chunk of game left and your not ready to play the Mirror of Mystery level, than wait to buy it. (See original comment. If Adventure Packs disappear faster than a speeding bullet in the New Zealand/Australia markets, then disregard my geographically inappropriate suggestion!)
Blackout and Spotlight are the new elements, so I wouldn't delay on them. Pop Fizz and Fyno....I would totally wait.
Reality Check...If you delay, you COULD miss out...Just the way it is...With the exception of Granite Crusher
, its worked out pretty well for me though.
4. Does EB games have the Gamestop equivalent of the Skylander Club? If so, join and get the 7th figure free. (Buy 6 figures, get a coupon emailed to you for a free 7th) That way you wait for a sale...get a discount...and contribute to the 6 figure count...earning your way to another discount. Video Game trade ins...?? Another possible source to defray the cost.
Anyway...pretty general advice...but it I hope it gets your thrifty,creative side fired up!