VAT exclusive price
The ex-VAT price is the displayed figure divided by one plus the rate. A 59.90 shelf price at 21% is 49.50 net with 10.40 of VAT. That net figure is what counts as revenue in your accounts.
How to find the ex-VAT price
Margin calculations must use ex-VAT figures on both sides, and this is the most common place people go wrong. Comparing a VAT-inclusive selling price against an ex-VAT cost inflates the apparent margin by the whole VAT rate, which can turn a 15% margin into an apparent 35%. VAT is not yours; it passes through the business to the tax authority. Stripping it out first is the discipline that keeps the numbers honest.
Questions
Divide the displayed price by 1 plus the rate. By 1.21 at 21%, or 1.20 at 20%.
The ex-VAT one. VAT collected is a liability owed to the tax authority, not income.
Almost always because the selling price includes VAT and the cost does not. Strip VAT from both before comparing.
Turnover for the threshold is the VAT-exclusive value of taxable supplies. Check the local rule, as definitions differ.
In this context yes; both mean the amount before VAT is added.