Going to link Gundam Planet's page on the different Grades & Sizes for those interested.
https://www.gundamplanet.com/grade-comparison
Difficulty : Rated by amount of pieces, size of pieces, and time needed to complete.
Feature : Rated by flexibility, poseability, and sturdiness of the final product.
Detail : Rated by amount of decals included, amount of paint needed, and faithfulness of molded colors to the anime.
UPDATE: Amazon AU somehow has "sold out" (???) its preorder listing of the Wing Zero EW, or at least taken down, as the seller is no longer Amazon AU. Hence you may see the $43.19 pricing from other sellers.
There are a lot of Gunpla (a term directly transliterating the japanese term for Gundam Plastic Models) deals lately. Preorders mean it'll satisfy your FOMO but if you have buyer's regret later (due to whether already too many to deal with or costs getting out of hand), just cancel away, you won't be charged until it ships (although sometimes it might come back in stock before the quoted date).
No idea whether the Wing Gundam Zero EW (https://www.amazon.com.au/dp/B08VGGC4DS?smid=ANEGB3WVEVKZB) is the lowest price, but <$40 for a RG (Real Grade) seems to be decent being delivered in/to AU. Check 3camels for price history. Amazon page claims release date to be November 24, 2023 for the Wing Zero EW.
If the webpage images are to be believed, the kit seems to have the number 0194380, released in 2014.
Found a review by someone on the internet: http://elementalcheese.blogspot.com/2015/03/gunpla-review-rg…
$76.49 for the Freedom Ver 2.0 MG (Master Grade), number 0204883 released back in 2016: https://www.amazon.com.au/dp/B08XW97RRT
UPDATE: Just realised FrontlineHobbies is selling the Freedom kit at the same price, if you can pick up locally in its NSW location: https://www.frontlinehobbies.com.au/bandai-gundam-mg-1-100-f…
Justice (also MG) is at slightly higher price at $81.68 so while it seems to be the lowest price at the moment, but probably not amazing bargain price: https://www.amazon.com.au/dp/B09NDKWDMX .
October 20, 2023 is the release dates for the Freedom and Justice.
Another RG kit that I was able to find at $40 mark is RX-78-2 at $40.03$36.88 from Amazon JP via AU: https://www.amazon.com.au/dp/B08VXCYTYG/ref=mp_s_a_1_142?cri… , but considering the recent MG of it at $58.87, the $40 RG isn't amazingly priced.
Out of interest, are Gundam cheaper to buy in-store in Japan? Im back there in August (assuming they are easily found in Akihabara)?