If it's a variety of sounds, like clean / driven / downright dirty, then something like a Sansamp BDDI Deluxe or VT Deluxe would be ideal. If you need other effects from there, you can add them when you want.
On the other hand, if you need core sounds and effects right off, then a multi FX may well be a better option. The Zoom B3n is a relatively inexpensive and easy to programme / play with option if you only use a few effects. However, if you want to add more effects / use amp & cab sims etc. then something like the Line6 POD Go or HX Stomp might be worth a look.
On saying that, I've been using a Line6 POD HD500x for the last few years, which you can pick up second hand for about £200-250. You do have to register & buy the add on the HD Bass pack (about £20), but it does sound great IMO. Has all the effects & connectivity that you might need, and still costs less than the Helix variants.