Even though you were offered a commission only sales job, you should apply for unemployment benefits. One need not accept any old job that is offered just because one is unemployed. Would you accept a job offer as a crane operator on a construction site? Say a tower crane with a 1000 meter reach? If you have never done a particular job before and you don't have the skill set to do a particular job, you certainly wouldn't be expected to accept any job you are not qualified to do even if it were offered.
Have you previously done the type of sales required for the job you've been offered? If you are receiving unemployment benefits, you will be asked if you have turned down any job leads or offers. If you have, you will be asked why. In the case of tower crane operator, you would probably say because you are not qualified for that particular job.
In general, you are not expected to accept a job for which you are not qualified, or that will not pay as well as your most previous job. Once you have been looking for a job for a period, say a couple of months, then you will be expected to consider jobs that pay 10% less than your most recent job.
There are many reasons why you might turn a job offer down. Maybe it's too far to travel; you may not be qualified, it may pay far less than your most recent job, you may not have the necessary skills. Leads for jobs that fall into the categories I just listed can also be ignored. However, if there's a chance a job may suit you, then you should at least inquire about it, but inquiring is not accepting. By inquiring about the job, you demonstrate that you are making an effort.
Absolutely apply for unemployment benefits even if you do accept the sales job. Until you have a decent income from the sales job, it really doesn't qualify as having a job like the one you just lost. Every time you register for payment of benefits, you will be asked how much money you have made in the two weeks being questioned. If you took a job that was just for the day or a couple of days the money you report having made will be subtracted from your usual unemployment benefit., but it will not end your benefits, and you should receive the balance of your benefit minus whatever money you reported earning for the few hours, day, or a couple of days, etc.
From the way you describe it, the sales job isn't your cup of tea. If you decide to give it a try and you actually make some money at it, just report what you did make and assuming it isn't a lot more than you're expecting, the commission will just be subtracted from your usual unemployment benefit.
Personally, if it were me, I wouldn't even accept a commission only job that I wasn't certain would quickly build into a decent paying endeavor, and I've done sales many times over the years.
Apply for unemployment benefits.