LEGO Super Mario Adventures with Luigi Starter Course 71387 $59.99, Mario Starter Course 71360 $49.98 Delivered @ Costco

No doubt these will get cheaper over time, but for now this seems to be the cheapest to date. Membership required.

Lego Mario @ $49.98
https://www.costco.com.au/Baby-Kids-Toys/Toys/Building-Sets-…

Description
Introduce children to the interactive LEGO® Super Mario™ universe with this Adventures with Luigi Starter Course (71387). An awesome gift toy for trend-setting kids, it features a LEGO® Luigi™ figure that gives instant expressive responses via an LCD screen and speaker. Players earn digital coins for helping LEGO Luigi complete spinning seesaw and flying challenges, interactions with Pink Yoshi and defeating Boom Boom and a Bone Goomba. The nougat-brown-coloured bricks in this Tower biome also trigger different reactions from LEGO Luigi, and the ? Block offers extra rewards.

Creative fun
Find building instructions in the free LEGO Super Mario app, which also includes inspiration for ways to rebuild levels and more.

Unlimited possibilities
Collectible LEGO Super Mario toy playsets offer a new way to play, in the real world, with iconic Super Mario characters. The Starter Courses and Expansion Sets, plus Power-Up Packs, combine in limitless ways to allow fans to build their own levels.