cheap low spec machine brand new?? no youll soon realise its limitations and regret it and have to upgrade........
good priced better machine off e bay?? you ,may drop lucky but its a big risk in my opinion......
go on the for sale section on here, look for a machine for sale from a well known operator and advertise that your after one.......
personally id go for the third option if you dont want to lease a new machine from the off and start with a top bit of kit!!!!