Hey Manisha,

Regarding your query, at first I would like to inform you to go through the following Careers360 article:

https://medicine.careers360.com/articles/neet-cutoff-maharashtra

Though Commissionerate of Common Entrance Test (CET), Maharashtra has not released the official cut-off details for this year till now, after analysing the previous year's cut-off informations it can be atleast estimated that despite being OBC category candidate you don't have any kind of possibilities to get any BDS Government Colleges in Maharashtra this year.

To get any top BDS colleges in Maharashtra through OBC quota, you had to secure atleast more than 520-30 marks where your expected marks is 250 in NEET UG 2020. So I'm very afraid to suggest you to leave the hope of the topmost and renowned Government BDS colleges in Maharashtra with this kind of performance in NEET UG exam.

One thing should be mentioned in this regard is that there's a little hope to get admitted in several private BDS colleges in Maharashtra, if you wish you can atleast try for those. You can also use Careers360 NEET college predictor tool:

https://medicine.careers360.com/neet-college-predictor?icn=QnA&ici=qna_answer

However now coming to the second part of your query: listen Manisha, fees structure of any Government College in any state must be too much affordable for all students because they get all kind of financial supports from their respective Governments. The same thing is also applicable for all the esteemed Government BDS colleges in Maharashtra (i.e. fees structure of all these colleges are almost 4-5k per year). I can also refer you the following article to get a vivid perception in this context:

https://medicine.careers360.com/colleges/list-of-bds-colleges-in-maharashtra

Hope these informations and above links will be quite helpful for you.