Gibson 1958 electric guitars and amplifiers catalog, page 31. Details of two guitar amplifiers, the GA-20 and GA-30. 1958 zone 1 list price were as follows: Gibson GA-20 $169.50; Gibson GA-30 $180.
$700
$1100
$4000
$2499
$2350
$2495
$2700
$1200
£1950