Question about will/living will and if you don’t have one

Just wanting some information from anyone who has looked into it before. We don’t currently have any will or living will. We really want one but can’t afford it right now. I’m just wondering if anyone knows if there is a way to write a will yourself or any other way to have your wishes known in a way that will be followed or is the only way to have an actual will? Does it have to be done by a lawyer in order to mean anything? Also if you and your partner were to die at the same time and didn’t have a will in place what happens to your children? If a family member knows your wishes and immediately steps forward will they be given the children or do they always go into foster care at that point and then the system decides? What if multiple family members step forward? Sorry if these are stupid questions I’m just stressed that we don’t have one yet. And if anyone wouldn’t mind sharing how much exactly is it to have a will made and what does it include?