Depends on the broker and their charging structure - in particular any minimum charge that they impose. Working it out should not be difficult.what amount in value should you buy shares in order to optimise savings/costs.
Impossible to say without more information about your investment goals, timeframe(s), attitude to risk/volatility, other investments/savings/debts etc. etc.and i have a portfolio covering 10-12 companies, should i continue to expand these or should i bulk them up.