Keep in mind, you can technically write the plan yourself. That way you can dictate that the practices will be within you budget.
I can tell you my process when I get asked to do one of these.
*Figure out where you property is. If you have a nice, modern CAD, I've probably eyeballed it before we get off the phone.--call it 5-20 minutes. I'll usually try to set up a site visit within a week (some times 2)
*I'll probably spend about 3-4 minutes playing in Google Earth's most recent imagery.
*Then I'll spend about 3 minutes eyeballing your property in the the NRCS WebSoil Survey.
*From that, I'll pull a generic historic plants list/base line to play with and your soils maps
--So, at this point, I've spent a grand total of about 15-20 minutes on the matter.
*We do a site visit to ground truth my 20 minutes of playing on a computer.---depending on the vegetation types, I'm usually looking for specific plant species....generally I have 5 trees, 5 shrubs, and 5 grasses (specific to that properties ecoregion and specific location)I'll be looking for. I like things that are umbrella species, and generally really easy to spot---If we don't spot them, well, it's an easy base for the plan--We MIGHT spend 45 min-2 hours on the tour of the property.
*Then we have a tailgate (or preferably ice tea and food) meeting. With pretty maps (which hopefully you have) and the downloaded documents we walk/talk our way through the 7 broad practices, and choose 3 to YOUR liking.--Maybe 15-30 minutes
*At this point, it's up to you to fill in the documents. If it is picky county and wants a biologist's signature, you email it to me and you get an electronic signature on it.
*Really nice landowners bring a laptop to the tailgate meeting with the fillable documents filled in, minus the actual management plan. Sitting there, we can literally fill in the rest in 15-20 minutes and you are ready to submit.
Some of the TPWD biologists have a lot more time constraints. They may forgo doing a site visit, have you come into the "office", and fill in and sign right there. Talking about maybe an hour. Most of us have our favorite practices we turn to, and can write these plans pretty much in our sleep.
If you want to go through a private contractor, by all means do so. But if you want to do it yourself, you have every right to do so. If you want to write it yourself, then simply consult with a TPWD biologist (and/or get a signature) about whether or not it is effective or doable, we LOVE those types of consultations.