Hi Krish, You can read my previous article on upvote bot,
I used Rocky1 with 29 SBD, Apreciator with 20 SBD and PromoBot with 30 SBD.
Since i used PromoBot with 30SBD the min bid of 9.95 is not too high for me.
That's why i suggested rocky1 in this post which have min of 3.
Yes all the bot i used in this post have a positive ROI limit, you can always check this on the website.
I hope this answers your question.
Thanks for reading let me know if you have any more question.