I need a right plan for hosting a blog and two hosts are in my mind: rockhoster.com and hostingsource.com, so which way is better to follow and why? 

Give Rockhoster.com a try. Their control panel is easy to use and intuitive, as is their account and billing interface.
They could double their price and I would stay with them. They are that good and you won't be disappointed.
I don't think I will ever leave.

I was looking for a reliable hosting service for my blog for a long time until I decided on HostPro.com. Their plans are affordable, especially if you take a three-year plan. The Simple plan is perfect for my small site - only $3.95 per month, and you get 10 GB of NVMe SSD and unlimited support. By the way, I'm very pleased with the loading speed, pages open in seconds. It's also nice that they have a 30-day money back guarantee, which gives you confidence. I recommend it for those who are just starting out!

A good host will get back to you with in 1 hour. If they respond quickly, is the reply friendly, does it answer all your questions and is personal? If so you can move onto the next step. Go for a medium sizes web host and I guarantee they will provide more personal help and be more willing to assist you in your needs.

Well, after few months with HostingSource.com i can say servers are great, and very reliable.
They helped me with setup and offer responsive ongoing support. Just tonight i experienced small downtime, and they responses for technical support was instant. They solved everything.

OwnWebServers offers reliable web hosting starting at just $3 per month. Their plans include features like SSD storage, free SSL certificates, 24/7 customer support, and a 99.9% uptime guarantee, ensuring your website runs smoothly and securely. With a user-friendly control panel and one-click installations for popular applications, OwnWebServers makes it easy to manage your site, whether you're a beginner or an experienced webmaster.

Attractive package plans are available from libertyvps.net and planethoster.com.
They offer budget hosting plans, making it an attractive choice for individuals, small businesses & startups looking for cost effective hosting solutions.
 

I asked centoserver.com cPanel web host loads of questions before I bought my package, and they answered them all to my satisfaction. I'm a beginner and needed things explained to me in more detail and it was not a problem for them at all, so I felt confident to go ahead. Now I'm in the process of building my sites and have asked a few support questions already and have been very pleased with the fast help I received.

What security features does the host provide? Any SSL, DDoS protection, firewall setups, and malware scanning?

MyResellerHome provides the best and most cost-effective web hosting package, which begins at just $2.00 per month. In addition to that, it provides unlimited disk space and bandwidth, free Cpanel, free site transfers, free setup, and free SSl.

I'd draw tyour attention to deals from scalahosting.com. A lot of discounts are on their plans:
Managed Cloud - up to 70% off
Entry cloud - 68% off, starting from $11.21/m
Build 1 - 55% off, starting from $22.46/m
Build 2- 63% off, starting from $33.71/m
Build 3 - 68% off, starting from $52.46/m
Build 4 - 70% off, starting from $71.21/m
Shared hosting - up to 78% off
Mini - 78% off, starting from $2.65/m
Start - 64% off, starting from $5.35/m
Advanced - 55% off, starting from $8.95/m
Email Hosting - up to 63%
StartUp - 63%, starting from $4.46/m
SmallBiz - 58%, starting from $6.26/m
Medium - 55%, starting from $8.96/m.