Wait until you finish your Instrument Rating, as you will get a hell of alot more out of a simulator session, than just flying the thing visually.
If you are applying for a 737 job, a classic 737sim will be cheaper than an Airbus so go for that. But most airline sim checks will be held on traditional equipment Non-Efis so your scan has to be up to scratch, hence why you should invest in the IR first.
regards,
s744