You want:
insert into prices (group, id, price)select 7, articleId, 1.50from article where name like 'ABC%';
where you just hardcode the constant fields.
Try this:
INSERT INTO prices ( group, id, price) SELECT 7, articleId, 1.50FROM article WHERE name LIKE 'ABC%';
INSERT INTO prices (group, id, price) SELECT 7, articleId, 1.50 FROM article WHERE name LIKE 'ABC%'