can you by alcohol at costco with out a membership?

Nope

Yes, you can. All of these people saying no are WRONG. It is illegal to require a membership to sell alcohol. That's why the liquor stores at Costco all have separate entrances. You can also buy pharmaceuticals, wine, and beer by going into the main store. Tell the person at the front door and they'll let you in. This answer applies to Florida only.

You can't

No you can't buy anything without a Costco membership

No