The price hasn't been disclosed, will have to wait on that.

There won't be a discount, but rather you will get free cards if you buy enough. Plus you will get exclusive promo cards too if you buy in the pre-sale. Read more on that in the last AMA:

https://peakd.com/splinterlands/@brybro27/splinterlands-ama-summary-september-3rd-2021-2pm-eastern