Yeah, might be cheaper to get MP-10 Convoy and MP-22 Ultra Magnus online?

HobbyLink Japan still has them available (Magnus is the Feb reissue, but they can hold items for you for up to 3 months, so you can combine orders and ship together when they're all in stock)

Convoy, around $212 AUD:
http://www.hlj.com/product/TKT39840/Sci

Magnus , around $174 AUD:
http://www.hlj.com/product/TKT80320/Sci

Cost of shipping them together is around $65. (Also, MP27 Ironhide is out this month in Japan so you could chuck that in your order too)

Can't help with you with a cheaper Star Saber though. Is he still $300 at TRU?

I mean, if you're ok with TRU's prices, and the items you're buying aren't returns, you shouldn't have anything to worry about.