As a side note I am getting through the 60 'everyday' bottles I have from Cellarmasters.
However I have a bit of buyer's remorse for my first transaction when I purchased 3 cases (to use a lucrative voucher). Paying $3.55 per bottle is super cheap and a few wines are okay. But several of the wines are pretty nasty. I have taken to tasting a bottle. If I don't like it, I immediately put it in the kitchen and open something I trust. Said bottle is then used in cooking. Luckily I love cooking, so I have had a few white wine sauces and a regular bœuf bourguignon using the reds I haven't liked (so not real bœuf bourguignon, but close enough


).
I think the optimal way to use these offers is 1x cheap case for cooking (and the bonus points), then 1x case of something decent, which pushes the spend up to the voucher level and subsequently knocks down to a respectable price. Much as
markis10 suggested (and I copied) for the most recent bonus offer (with the Penfolds).