Hello, I am Mary Thomas, Attorney and CPA

I’m the type of person who likes to solve a good puzzle. I’ve always had a passion for pulling things apart and putting them back together, which means the nuances of sales and use tax is right up my alley.

There’s something rewarding in being able to take a situation, break it down and make it simple so people can understand what’s going on.

I’ve employed that approach as part of a lengthy career as both a Certified Public Accountant and an attorney.

The reality is, most people find out about their sales & use tax responsibilities at the worst possible time– during an audit.

I love empowering people so they understand exactly what they need to do, so they can rest easy in the knowledge they understand sales and use tax and are doing it right.

How I can help you

Using both my legal expertise and accounting experience, I’ll provide you with the resources and research you need to ensure your business is compliant when it comes to sales & use tax.  

Not only will I find the right information to suit your individual needs, I’ll give you the research and discuss it with you, so you can comfortably approach sales & use tax in the future.

Start-up Consultation

Did you just start your business, add a new product or service line, or expand your territory?

Whether you are just starting out or are expanding your business, we walk you through questions about registration, taxability, and the account set-up and report filing process.

Nexus Study

Not sure if you need to register to collect sales or use tax?

Nexus Studies are for people who are concerned that they may have a duty to register to collect sales or use tax in states other than the state of domicile.

Learn about Nexus

Concerned about nexus (the requirement to register to collect sales or use tax) and want to learn the basic framework of how to perform the analysis on your own? 

In the academy, I share with you tips on how to understand and navigate the world of nexus in its different forms.

Sales Tax Compliance Consultation

Think you might have made a sales tax mistake? I can help you with that.

We will work to determine if there is an error, quantify it, and craft a plan of action to correct it.

What Others Say About Mary

Taxes always seemed daunting.  However, I was given the task of working with sales tax for a green field operation.  Shamefully, I dreaded the process and wasn’t looking forward to my ‘Intro to Sales Tax’ with Mary Thomas’ company.  As soon as met Mary, I knew I had found not only a thorough and patient teacher, but an expert in her field. 

Stephanie Bryars at RavenChem

Prior to our commencement of working in Texas we searched many firms looking for the right fit.  The minute we started talking to Mary we knew we would have a lasting relationship.  She knows her business. The methodical approach in teaching and explaining the rules governing sales and use tax is upbeat and comprehensible, especially for a firm doing business for the first time in Texas. 

Lori Potokor at Midway Enterprises, Inc..

Opening up a small business is much more difficult than it appears on any Hallmark Channel movie. There are so many moving parts: payroll, insurance, rent, etc. For questions about sales tax, a friend recommended Mary Thomas. She answered all my questions…and repeated those answers in a very courteous and knowledgeable way. You will definitely feel more confident and empowered after making her part of your team.

Sam Malone at 512 New Media

The Top 5 Sales Tax Resale & Exemption Certificate Mistakes

The Top 5 Sales Tax Resale & Exemption Certificate Mistakes

When working with sales tax, it is common for people to sell items that are not taxable without collecting resale or exemption certificates that support the tax-free nature of the sale. If a taxing authority requires the collection of the documents to prove that your decision not to collect sales or use tax was correct, you MUST have the documents. And there is a difference between resale and exemption certificates.

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Reach Us


11615 Spring Cypress Road, Suite E 
Tomball, TX 77377-8920





Contact The Sales Tax Sisters