Why do most beginners lose money in search arbitrage?
Margins are thin and mistakes are paid for in cash. Newcomers typically misread the metrics, test too few creatives and keywords, trust estimated revenue, run out of money before the feed pays, or lose an ad account or feed to a policy breach. Experienced teams also lose on most tests; they simply stop losers faster and fund winners longer.
The common errors are specific. Comparing feed RPC per ad click with traffic CPC per visitor makes a losing campaign look profitable. Judging a campaign in its learning phase leads to stopping too early or too late. Ignoring the gap between estimated revenue and finalised revenue overstates profit. Underestimating the cash-flow float forces a stop just as something starts to work.
Then there are the hard stops: an account ban on the traffic source or an feed suspension on the feed. Both often follow copying aggressive creatives seen in a spy tool. A beginner's edge, if there is one, is patience, small budgets and strict compliance, not a secret keyword.