I would suggest (as, obviously, would the majority of posters here) that your situation is quite complicated, actually. You have at least one immigration refusal/bounce on your record. You overstayed your visa for 4 years and used public health systems while doing so, which is frowned upon (not to mention illegal). The standard application is pretty easy to process/get approved, but due to those 2 factors, your application is far from standard.
(I would also question how you can prove adequate finances if you don't have the funds to apply for the visa, which would throw another wrench in the works.)
Basically, it's a question of whether you're willing to potentially throw the application fee down the drain if it gets refused, and have to either reapply (and pay the fee again) or go through an appeal (which would benefit from professional/legal advice and would involve fees as well). If that's the case, then do it all yourself, and good luck. If you want to be (reasonably) sure that your application will be accepted and you can be reunited with your husband again, come up with the money to seek professional/legal advice before you submit your application.