Historically one of London’s legal centres, Holborn doesn’t have much to offer cheapos at first glance. That said, there are some surprisingly good (and cheap) local pubs and restaurants if you know where to look. The famous jewellery quarter of Hatton Garden, near Farringdon station, is also a good spot shop around for (relatively) affordable bling.
London Sightseeing by Bus: Nature, Architecture and Historical Landmarks
The no-stress option for taking in the city's aesthetics and most famous views.