For starters there are a number of articles which call out the possiblity of doing User research on a low or non existent budget. A good article to start would be 10 Tips on Doing User Research with No Budget which has provides 10 different ways you can get research data without having to spend any of your budget.
To briefly quote some of the points in the article
- Use existing analytics. If you are redesigning a site or product, review all existing data on traffic patterns, errors, and any survey
results since the product’s last launch. Get a sense for what is going
right and what is going wrong with the existing product. Don’t expect
a single point of contact on the client side to have all the
information you need. Do the leg work and pull the data together.
- Add the call center to your list of stakeholders to interview. If your client has a call center, interview the call center employees.
Observe the call center at work if you can, even just an hour is
great. The call center knows better than anyone else in the business
what the user problems and perceptions are. When you interview
stakeholders, ask them about analytics. Try to make questions
open-ended so the answers can surprise you. Surprise is good.
- Identify key scenarios. Once you’ve reviewed existing analytics and aggregated stakeholder requirements, you can begin to sketch out key
user scenarios. Make sure these scenarios come with measures of
success so you can plan to gather analytics for the next product
launch. UX is cyclical – line up your next success early. Ground
scenarios in the return on investment they can demonstrate.
- Mock-up the concept by any means necessary. Sketches, HTML prototypes, iRise, Axure, comps; use whatever works for your timeline
and your team to get the concept to a point that it can be shared.
It’s better to get user feedback too early than too late.
Another good article to look at the UX Myths article Myth #22: Usability testing is expensive which has this to say about conducting usablity testing
Many organizations still believe usability testing is a luxury that
requires an expensively equipped lab and takes weeks to conduct. In
fact, usability tests can be both fast and relatively cheap. You don’t
need expensive prototypes; low-tech paper prototype tests can also
bring valuable results. You don’t need a lot of participants either,
even 5 users can be enough to test for specific tasks, and the
recruiting can also be done guerilla-style. For many projects, you can
even use remote and unmoderated tests.
I also strongly recommend looking at this article about how to conduct UX interviews on a low or non-existent budget to drive a better understanding of users. To quote the article
User interviews are also easy on a project budget. Other methods, like
eye-tracking, usability testing, participatory design or even surveys,
can use up budget hours. These types of field interviews are best used
before a project really begins, but they can also happen during the
interaction design phase. The key is to focus on quality over quantity
in selecting the right users. One of your team members can conduct
three user interviews in the course of a morning or an afternoon, and
if you have designed good questions, your data should be easy to read
without adding lots of hours of analysis time.
I also recommend looking at Hallway testing as a way to quick user evaluations and get an understanding of the challenges faced by the user base.
I also recommend looking at this question What ways to conduct user research quickly and cheaply are there? for additional inputs
I also recommend looking at this excellent article Five Techniques for Getting Buy-In for Usability Testing. To summarize the article
Start Testing Right Away Start testing. Start doing it right away. We’ve found there isn’t any one experience more beneficial to design
teams than running a usability test. I’m still amazed by how quickly
development team members recognize the benefits of usability testing
once they’ve actually seen it in action.
Debunk the Myth that Usability Testing Is a Big Production One of the biggest obstacles design teams face when trying to sell testing is
the perception that usability tests need to be a huge production.
The best way to tackle this resistance is by debunking the myth that
testing has to be a big deal. Usability testing isn’t rocket science.
The organizations that do the best job of incorporating usability
tests into their existing process understand that testing is not a big
deal.
The best organizations make usability testing a part of their everyday
culture. To convince management that testing doesn’t need to be a huge
production, we recommend design teams start simple. You can start by
testing 3-5 users and disseminate that information throughout your
organization.
Start Testing Early in the Process Many organizations are concerned that testing will disrupt project timelines because it may
necessitate major design changes before launch.
However, time and time again, we find that design teams actually save
time (and money) when they start testing at the beginning of a
project. By finding usability problems very early on, teams prevent
themselves from going in the wrong direction, leading to wasted time
and resources.
The most successful teams have learned that the best way to create
usable designs is to make informed decisions from the beginning of a
project. They view testing as a technique to gather information to
create great designs in a more timely and efficient way.
Involve Management and Stakeholders To get buy-in from team members and management, it’s essential to keep them involved. On every
project, we suggest that stakeholders sit and observe at least one
usability test. This will give team members the opportunity to observe
first-hand the information gathered from tests.
Identify Your Organization’s Champions and Address Their Needs
Finally, one of the best ways to get buy-in is to identify which
members of your organization will benefit most from usability tests
and recruit them as your Champions, assisting to rally other members
of the organization