Basic rule of thumb for all stringed instruments (including basses), play as many as you can and pick the one that feels right in the hands and whose tone speaks to you the most. Then if it's a bowed instrument spend at least 10% of what you've spent on the instrument on a bow. That kinda rules out the Tesco violin, but it probably comes with a bow anyway. Cheap instruments can deter learners if they are nasty as well as cheap i.e. strings you can limbo under, sound post in the wrong position, crap strings etc all of which can make the whole thing a lot more difficult than it needs to be.
When I bought my current 'cello 20 odd years ago it was better (to me) at 6K than another I played in the same shop at £30K.