The Webly 400 series action was the basis for a lot of 'Trade' guns and was the precursor to the 700.

Non-ejectors built on this action bearing lots of names of provincial retailers or gun makers are very commonly available for not much money.

Any gun of this type built between around 1900 and 1930 should be available for well inside your budget(£500 will do the job here).

They are well-built, reliable and decently balanced and finished.