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please suggest some proven tool for bulk cold email marketing at reasonable pricing. Should not spam or have limits/restrictions.

The cheapest one and probably one of the  best would be:
<https://www.apollo.io/>

But again if you do Bulk Cold Email you first should focus on warming up the email domain you have, and I would suggest for you to create multiple email domains and not use your main domain for your campaigns.

+1 to what Stefan said. There are also lead gen agencies that specialize in a tech stack/certain tools, so if you're new to email outreach, I would consider partnering with an agency for the first few months once you've decided on tooling for outreach/CRM