There is no minimum purchase required for the free standard shipping offer and if you sign up for their free My Best Buy rewards program, there is no minimum purchase required for the free next day shipping for qualifying items.
According to their website, "Next-day delivery for qualifying products is based on product availability and on the time of day the order is placed. $35 minimum purchase is required and applies to ship-to-home items after coupons and before taxes. $35 minimum does not apply to My Best Buy Elite and Elite Plus members."
There are some restrictions for larger products, no Sunday delivery, during Thanksgiving week and more.
For many products, you can order online and pick the item up at your local Best Buy in an hour with no shipping fees.