So glad to hear you are reaching out for help. I'm so sorry you've been through domestic violence. Therapy can be really helpful for that.
As far as pricing, providers on the platform don't handle billing or subscriptions, so your best bet there would be to email support for a more detailed answer on how to pay for biweekly instead of weekly. Here's the website with their contact info: https://www.betterhelp.com/contact/.
In the meantime, there a lot of resources for domestic violence that can be helpful when waiting on counseling. Here's a few that have really good resources:
Depending on the area you live in, you may qualify for assistance or insurance that pays for most of the cost of counseling. This also depends on what platform you engage with or if you choose to go in-person, but most of the time, most clinics will have sliding scales to meet your financial needs.
One thing I want to point out is that you said you are a domestic violence survivor. That's a strengths-based statement! If you have made it through domestic violence, you have so many strong qualities that maybe you aren't aware of yet. I don't know if you are away from your abuser or what the circumstances are, but either way, many of the effects of domestic violence can follow you into areas of your life even when the abuse has stopped. Whatever you did to get through the abuse, you can use or modify to help you get through what life is like for you right now. You are also strong enough to ask for help and seek out therapy, so you are obviously very motivated and have not given up in the slightest!
Not sure where you live, but sometimes there are organizations as well that are meant to help with domestic violence issues. Here in Wisconsin where I am located, we have a place called Embrace. Here's the link to that: https://www.embracewi.org/. You may have something similar in your area.
Either way, I hope you find what you are looking for that fits your budget and needs best!
I am wishing all the best for you and your path to healing!