Two hundred dollars gets you to conversations. It does not get you through a full follow-up cycle, which is where most of the real spend sits.
Rough shape of a starting month. A four hour driving session might cover 40 or 50 miles, so call it $10 to $15 of gas. Owner names and tax mailing addresses come from county assessor records, which are free online in most counties. Phone numbers cost, usually 10 to 30 cents per matched record from a skip tracing service. Postcards through a mail service run roughly 40 to 80 cents delivered. An app subscription, if you use one, is commonly $50 to $100 a month at the entry tier, and you can skip it at the start with a spreadsheet.
So 150 logged addresses, 100 traced, 150 postcards mailed once, plus gas, lands somewhere near $120 to $150 without a subscription. That is genuinely a first-conversation budget.
The part that breaks beginner budgets is that one mailing almost never works. Owners of neglected property are often not ready the week your card arrives. Operators plan on five or six touches spread over many months, which turns those same 150 addresses into $500 to $700 of mail over a year. If you budget for one touch you'll conclude the strategy doesn't work when what happened is you stopped early.
Keep a mileage log from the first drive. Vehicle expenses and marketing costs for an investing activity are usually deductible in some form, and the treatment depends on how your activity is classified, which is a conversation for an accountant rather than a forum.