The fact is that online transactions do require an email address. You can always setup a separate email account, or use an alias email address for online purchases, such as offered by Microsoft Outlook.com. It forwards emails to your primary account. You can even send/reply to email using the alias@outlook.com. The business never sees your actual email address.
GMail does have one of the best anti-spam systems of all email providers. You can use it in an indirect way by auto forwarding your current email to a Gmail account if possible? Then set the
"Reply to" option in GMail so email responses will still be sent to your current email account. Basically, you end up using GMail instead to read/write/reply, while still use your old email address.
If you're not already doing so, you may be able to use an email client to manage your account. Such as Outlook or Thunderbird. Many of which support multiple spam filtering options.
But yet another method is to use email filters. I have over 10 different email accounts managed through Thunderbird. I used to be inundated with unimportant emails from the likes of Newegg, Redbox, Ebay, Groupon, Alumni Assoc, other non-profit orgs, etc which tend to clutter your Inbox. The simple solution is to just unsubscribe to them. But some contain info I may be interested. Just only when, and if I have the free time to do so.
By using filters, these less than important emails get auto sorted into a separate folder for Review. The result being that I have been able to reduce emails in my Inbox from about 50-60 a day, to less than 10 total across all accounts. Sans my enterprise email, which requires special access. I also have the Review folder auto trash emails if I don't get around to read them after a certain number of days. Those in my Inbox have to be manually deleted.
Note that order invoices and receipts from online transactions do not get filtered, and still arrive in my Inbox. Most businesses use separate sub-domain address for them, so doesn't get mixed up with other news or offers.
