The short answer is generally yes, but also.... it depends.
The long answer is also... it depends. The first question is what (or who) is actually being sanctioned, second who is impacted by the sanction, third what is the specific sanction? There are a variety of different types of sanctions, sanctions against the state, businesses, people, etc. Most sanctions for example are against specific people, or conduct like investment or movement of capital, not necessarily the purchase of goods. I go into further discussion below, but for the quicker answer to your specific question, unless the person you are buying from is directly sanctioned or the subject of sanctions, or the entities specifically involved in the sale of goods (export company, vessel, etc) are directly sanctioned (or Russian companies operated in Crimea), yes it would be legal to purchase. So yes, unless the specific item you are buying/ entity you are buying it from is specifically sanctioned it would be legal, it is not particularly common for sanctions to prohibit the purchase of goods by consumers, unless there is a unique circumstance.
Here is the 2-3 page overview of U.S. sanctions on Russia: https://sgp.fas.org/crs/row/IF10779.pdf
As to the further discussion. For example see below, many current sanctions are against government officials; Or in the case of EO 13685 from 2014 concerning the occupation of Crimea many of the sanctions imposed aren't strictly against Russia, but instead prohibits U.S. business, trade, or investment in occupied Crimea.
EO 13685 excerpt:
Section 1. (a) The following are prohibited:(i) new investment in the Crimea region of Ukraine by a United States person, wherever
located; (ii) the importation into the United States, directly or
indirectly, of any goods, services, or technology from the Crimea
region of Ukraine; (iii) the exportation, reexportation, sale, or
supply, directly or indirectly, from the United States, or by a United
States person, wherever located, of any goods, services, or technology
to the Crimea region of Ukraine; and (iv) any approval, financing,
facilitation, or guarantee by a United States person, wherever
located, of a transaction by a foreign person where the transaction by
that foreign person would be prohibited by this section if performed
by a United States person or within the United States.
(b) The
prohibitions in subsection (a) of this section apply except to the
extent provided by statutes, or in regulations, orders, directives, or
licenses that may be issued pursuant to this order, and
notwithstanding any contract entered into or any license or permit
granted prior to the effective date of this order.
(And even then sanctions may apply, unless they don't...)
CRS Report:
The United States has imposed sanctions related to Russia’s invasion
of Ukraine on at least 735 individuals, entities, vessels, and
aircraft that OFAC has placed on its Specially Designated Nationals
List (SDN) or Sectoral Sanctions Identification List (SSI) (see Table
1 and Table B-1). The basis for most of these sanctions is a series of
four executive orders (E.O.s 13660, 13661, 13662, and 13685) that
President Obama issued in 2014.15 In addition, the Department of
Commerce’s BIS denies export licenses for military, dual-use, or
energy-related goods to designated end users, most of which also are
subject to Treasury-administered sanctions.
Two of President Obama’s
Ukraine-related E.O.s target specific objectionable behavior. E.O.
13660 provides for sanctions against those the President determines
have undermined democratic processes or institutions in Ukraine;
undermined Ukraine’s peace, security, stability, sovereignty, or
territorial integrity; misappropriated Ukrainian state assets; or
illegally asserted governmental authority over any part of Ukraine.
E.O. 13685 prohibits U.S. business, trade, or investment in occupied
Crimea and provides for sanctions against those the President
determines have operated in, or been the leader of an entity operating
in, occupied Crimea.
The other two E.O.s provide for sanctions against
a broader range of targets. E.O. 13661 provides for sanctions against
Russian government officials, those who offer them support, and those
operating in the Russian arms sector. E.O. 13662 provides for
sanctions against individuals and entities that operate in key sectors
of the Russian economy, as determined by the Secretary of the
Treasury.
https://sgp.fas.org/crs/row/R45415.pdf
https://www.trade.gov/country-commercial-guides/russia-sanctions
See further references below:
https://www.federalregister.gov/documents/2014/12/24/2014-30323/blocking-property-of-certain-persons-and-prohibiting-certain-transactions-with-respect-to-the-crimea
https://home.treasury.gov/policy-issues/financial-sanctions/faqs/topic/1576
https://home.treasury.gov/policy-issues/financial-sanctions/sanctions-programs-and-country-information/ukraine-russia-related-sanctions
https://home.treasury.gov/system/files/126/ukraine_overview_of_sanctions.pdf
