You can access the USC code for free on GovInfo or via The Office of Law Revision Counsel United States Code. There are multiple tools available to you suchaas a search and browse feature, you can also search via the Popular Name Tool, and update you findings for free via the cite checker option. 

Some of the same access tools you use for the print edition are also available on Westlaw Prescision and in Lexis+.

A. Your search options in Westlaw Precision

1. Terms and connector search, or as natural language search.
2. Try using the electronic index. Remember there are two different ways to search, one is using keywords and the other is utilizing an index.  The strength of an index is that the index uses controlled vocabulary.  Controlled vocabulary means that one term is selected by the indexer and all the various terms which may signify the same idea are listed under that term.  Think of all the various terms used to express the idea of two people living together.  An indexer will list all of those terms under one term it helps you to navigate your way to the right statute.
3. Try exploring via the  'poplar name table search option'. If you have that information available it will be breeze to locate your statute! Keep in mind that many laws end up acquiring popular names as they make their way through Congress. In Westlaw Precision this search option is made available to you!. Sometimes the popular names reflect the substance of the law and sometimes the name may acknowledge the sponsor of the law.  But sometimes the name is simply catchy.
4. Try exploring the  Conversion ‘Table' search option.. This table provides a cross reference between a session law cite (Public Law or Statutes at Large) and a cite  to the code cite.
5. Always rember to exploring the statute's TOC (table of contents): When you click on the USCA in Westlaw Precision, you will see the laws arranged by Title, chapter and section.  You can drill down through the this ‘Table of Contents’ to view all of the section under a chapter.  This can be very useful as it allows you to see related laws which may be of interest to you or your client.

B. Your search options on Lexis+:

    There are only two search options available to you.

1. Either as a terms and connector search, or as  natural language search (These options are also available on Westlaw Precision
2. or by searching via the TOC search option (table of contents).

The truly best search option is of course to locate your statute via a known citation. But, no worries. The methods listed above work well too. Remember code means arrangement by subject.  Exploring via an index will be a time savor when you do not know the citation for the statute you are seeking.